Sterols,steryl esters and fatty acids in some Vicia faba seeds

Free and esterified sterol levels in seeds of five cultivars of Vicia faba were determined. Sitosterol was the most abundant free sterol, followed by stigmasterol and campesterol. Cholesterol could not be detected. Esters were generally present in greater quantities than the free form of the sterols. The fatty acid content of the plants is also reported.     

Sterols and fatty acids of aflatoxin and non-aflatoxin producing isolates of Aspergillus

The fatty acids and sterols present in 5 isolates of Aspergillus flavus and 3 isolates of A. parasiticus were determined; 2 isolates within each species were aflatoxin producers. The 4 major fatty acids were 16:0, 18:0, 18:1 and 18:2 with a trace of 15:0 in one isolate and traces of 17:0 in 3 other isolates. Cholesterol, ergosterol and 5, 7-ergostadienol were present in all isolates; the 5 isolates of A. flavus could be identified on the basis of retention times of minor sterols present. There was no correlation of total lipids, fatty acids or sterols with the production of aflatoxins. Water soluble complexes of sterols were not detected.     

Sterols and fatty acids of the marine diatom biddulphia sinensis

Nine sterols, most showing Δ⁵- or Δ^5,22-unsaturation, were identified in the marine diatom Biddulphia sinensis. One sterol, cholesta-5,22E-dien-3β-ol, comprised 70–80% of the total sterols which is the first such predominance noted in a diatom. The only Δ⁷-sterol detected was cholest-7-en-3β-ol and this was a very minor component. A sterol showing unusual side-chain alkylation,23,24-dimethylcholesta-5,22E-dien-3β-ol, was identified for the first time in a diatom. Total fatty acids exhibited a predominance of Δ⁹- 16:1, 14:0, 20:5 and 16:0, typical of diatoms, although the proportions of these acids were found to vary with culture maturity. n-Heneicosahexaene was the major hydrocarbon together with a small amount of squalene.     

Sterols and fatty acids of an antarctic sea ice diatom, Stauroneis amphioxys

Unialgal clonal cultures of the diatom Stauroneis amphioxys Gregory, isolated from sea ice of the Indian Ocean sector ofthe Southern Ocean, were grown at 3° and 20°. The relative abundances offatty acids, sterols and phytol for the two cultures are comparable. The two sterols observed [24-methylcholesta-5,22E-dien-3β-ol (79%) and cholesterol (21%)] did not vary with culture temperature. The-major fatty acid composition is typical ofmost diatoms. A pronounced change of ratio with temperature occurred with the pair 16:4 Δ6, 9, 12, 15 and 16:3 Δ6, 9, 12 followed by 18:4 Δ6, 9, 12, 15:18:3 Δ9,12,15 and 20:5 Δ5,8,11,14,17:20:4 Δ8,11,14,17; thus the relative abundances of 16:4, 18:4, 20:5 and 22:6 increase at the lower growth temperature. The total amounts of unsaturated acids do not change with temperature suggesting an effect on the final desaturase step. No cryoprotective role for such changes in lipid composition was inferred.     

Sterols, fatty acids and free amino acids from two Helvella species

Sterols, fatty acids and free amino acids of Helvella crispa and H. monachella were investigated. They contained traces of ergosterol and a high amount of ergosta 5.22-dien-3β-ol. Linoleic acid and l-Dopa are the most abundant fatty acid and free amino acid, respectively. The aqueous extract of H. monachella inhibits prostaglandin release by rat peritoneal leucocyres in vitro.     

Sterols from some black sea ulvaceae

The free and esterified sterol composition of Ulva rigida and Enteromorpha linza (Ulvaceae) from the Black Sea was investigated. The main sterol component of Ulva rigida was identified as fucosterol. The influence of the season and water pollution on the sterol composition was investigated. The origin of the C₂₆,- and C₂₅-sterols and of saringasterol in these seaweeds is discussed.     

Sterols from some sponges

The sterol composition of four sponges was determined by a combination of gas chromatography and mass spectrometry. Cliona viridis and Chondrosia reniformis contained mainly C₂₇-C₂₉Δ⁵ mono- and di-unsaturated sterols. Halichondria bowerbanki and Hymeniacidon sanguinea contained stanols and Δ⁵-sterols. Cholestanol was the major component of the sterol mixtures.     

Sterols and fatty acids from three species of mangrove

The hydrolysis of steryl esters on thin-layer chromatographic plates by porcine pancreatic lipase is described. The sterols and fatty acids produced were separated on the same plate, recovered, and analysed by gas-liquid chromatography for their compositions. Synthetic cholesteryl esters containing various saturated and unsaturated fatty acids and synthetic steryl oleates with various sterols were lipolysed along with steryl esters of Acanthus ilicifolius, Bruguiera gymnorhiza and Rhizophora mucronata mangrove leaves. The major sterol was sitosterol which was accompanied by cholesterol, campesterol, stigmasterol and 28-isofucosterol. In addition, stigmast-7-en-3β-ol was present in R. mucronata leaves. The component fatty acids found in all three species were 16:0, 18:0, 18:1, 18:2 and 18:3. The relative proportions of the sterols and fatty acids were significantly different from the chemotaxonomic standpoint. The results obtained by carrying out plate lipolysis for 45 min at 40° compared well with those produced by conventional chemical hydrolysis.     

The sterol and fatty acid compositions of seven tropical seagrasses from North Queensland,Australia

The sterol and fatty acid compositions of fresh leaves of the seagrasses Cymodocea serrulata, Enhalus acoroides, Halodule uninervis, Halophila ovalis, H. ovata, H. spinulosa and Thalassia hemprichii are reported. The major fatty acids were palmitic acid, linoleic acid and linolenic acid as expected. H. ovalis and H. ovata were characterized by the relatively high abundance (ca 5%) of the acid hexadeca-7,10,13-trienoic acid (16:3<7 > ). The sterol compositions were typical of higher plants, with sitosterol and stigmasterol accounting for 60–90% of the observed sterols. 28-Isofucosterol was a major sterol (20–30%) only in the Halophila spp. Cluster analysis of the sterol composition data clearly separated the Halophila spp. from the other seagrasses and enabled the distinction of Enhalus sp. from Cymodocea, Halodule and Thalassia spp. The seagrass species were clearly separated into five chemical groups using the combined fatty acid and sterol composition data and the need for a reappraisal of the taxonomic position of Halophila was indicated.     

Identification of natural and semisynthetic ω-cycloalkyl fatty acids

The experimental criteria, principally GLC behaviour and spectroscopic data, by which ω-cycloalkyl fatty acids (cyclobutyl to cycloheptyl, C₁₄ to C₂₁) can be identified, are described.     

Effect of cultural conditions on the sterols and fatty acids of green algae

Six species of green algae were grown autotrophically, photohetrotrophically, and heterotrophically and their fatty acid and sterol compositions determined. Sterol composition was higher in autotrophic than in heterotrophic plants by a factor of from 2 to over 20 in five of the six species studied. Relative amounts of various sterols did not change significantly with cultural conditions. In five of the species studied, autotrophic growth produced a significant increase in the relative proportion of linolenic acid compared to that in heterotrophic or photoheterotrophic growth. This increase was usually accompanied by a corresponding decrease in oleic or linoleic acids or both.     

Sterols of some chilean algae

The distribution of sterols in 14 Chilean Rhodophyceae and in Lessonia sp. (Phaeophyceae) has been examined. Cholesterol is present in all the red algae examined. Golidium filicinum contains, in addition desmosterol and 24-methylene-cholesterol. Cholest-7-en-3-β-ol was found in Cryptonemia angustate and Neoagardhiella gaudichaudii. Fucosterol and 24-methylenecholesterol were found in Lessonia sp.     

Signature fatty acids in the polar lipids of acid-producing Thiobacillus spp.: Methoxy, cyclopropyl, alpha-hydroxy-cyclopropyl and branched and normal monoenoic fatty acids

Abstract The polar lipids of 5 species of Thiobacillus were extracted and purified. An analysis of the fatty acid composition of the polar lipids documented the presence of methoxy, cyclopropyl, monounsaturated and hydroxycyclopropyl fatty acids of sufficiently unusual structure to serve as 'signatures' for the presence of these organisms in environmental samples. The structures of the unusual fatty acids of the polar lipids were confirmed by mass spectrometry (MS) after isolation by capillary gas chromatography (GC).     

被子植物起源研究中几种观点的思考

对被子植物起源研究中的几种观点进行了讨论。(1)由于被子植物存在着一组共同的性状,它们不可能是从不同祖先起源的,而是有着共同的祖先。被子植物是一个单源起源的类群。现存被子植物分类系统是依据包括形态学(广义)、分子系统学、古植物学和植物地理学等的综合性状建立的,只能表示出现存类群的亲缘关系并且追溯到它们最近的祖先。人们现在还不可能建立一个包括全部已绝灭的类群和现代生存类群的谱系发生系统。因此,现存被子植物分类系统只能看作是“亲缘”系统。(2)分析了用于推测被子植物起源时间的分子、化石和地理分布证据。我们认为,要确定被子植物起源时间,植物化石是一类重要证据,但化石只能说是植物本身可保存部分和当时当地所提供的化石条件的综合反映,它们不可能就是植物类群或种的起源时间。人们还必须考虑到化石本身的演化历史。应用分子钟也是一种手段,但误差比较大。如果我们除了利用上述两种资料之外,根据植物类群的现代分布格局及其形成,把植物的演化同地球的历史和板块运动联系起来,以推断它们起源的时间,这无疑会增加其可信度。通过对56个种子植物不同演化水平的重要科属地理分布的研究结果,我们曾提出被子植物的起源时间可能要追溯到早侏罗世,甚至晚三叠世。(3)分析了基于分子证据所提出的被子植物基部类群——ANITA成员(包括无油樟科Amborellaceae、睡莲科Nymphaeaceae、八角目Illiciales、早落瓣科Trimeniaceae、木兰藤科Austrobaileyaceae)的性质,讨论了ANITA成员在现代几个被子植物分类系统中的系统位置的不同观点,评价了它们的形态学(广义)性状。指出ANITA的成员由于包含大量的祖征,是属于原始的类群。但由于它们的共有衍征很少,如花粉球形,说明它们在被子植物演化早期就分道扬镳了,沿着不同的传代线分化。因此ANITA是一个源于不同传代线的复合群。     

Sterols of roots and nitrogen-fixing root nodules of some non-leguminous species

Sterols of both roots and nodules of three species of Alnus were found to consist only of sitosterol, whereas Casuarina cunninghamiana contained substantial amounts of campesterol, stigmasterol and sitosterol. In all four cases more sterol was extracted from nodules than from roots.     

Free fatty acids, neutral and polar lipids in Hordeum vulgare exposed to long-term fumigation with SO2

Three 9-day-old cultivars of Hordeum vulgare L. (Barberousse, Gerbel and Panda) were exposed to low levels of SO₂ fumigation (40 ± 5 and 117 ± 20 ppb). After 48 days of treatment the seedlings were harvested for lipid analysis. In comparison to the control (plants exposed to charcoal-filtered air), the total lipid content of fumigated seedlings declined at 40 ppb SO₂ and even more so at 117 ppb in all three cultivars. A large reduction in diacylglycerols. polar lipids and free sterols was also observed after fumigations at both SO₂ concentrations, whereas the treatments resulted in an increase in triacylglycerols and free fatty acids. The percentage composition of total fatty acids and that of each lipid class were changed by the fumigations. resulting in an increase in the degree of unsaturation. No changes in the percentage composition of sterols occurred in the fumigated leaves. These results suggest that even if SO₂ may not directly oxidize unsaturated fatty acids at the low concentrations used here (which do not cause visible injury). it may alter lipid metabolism. This alteration. which was particularly evident in the polar lipids and sterols, could affect the functions associated with membrane stabilization, in which lipids plus sterols play a key part.