Separation and determination of glycolipids from edible plant sources by high-performance liquid chromatography and evaporative light-scattering detection

Glycolipids from edible plant sources were accurately quantified by silica-based, normal-phase high-performance liquid chromatography using an evaporative light-scattering detector. Five major glycolipid classes (acylated steryl glucoside, steryl glucoside, ceramide monohexoside, monogalactosyldiacylglycerol, and digalactosyldiacylglycerol) were separated and determined with a binary gradient system consisting of chloroform and methanol/water (95∶5, vol/vol) without any interference from other lipid classes and pigments. The described method was applied to 48 edible plants available in Japan including cereals, legumes, vegetables, and fruits. Examined plant species contained glycolipids in wide concentration ranges, such as 5–645 mg/100 g tissue.     

Comparative citrus fatty acid profiles of triglycerides,monogalactosyl diglycerides,steryl esters and esterified steryl glucosides

Vesicular lipids from six orange and two tangor varieties were extracted, purified and separated by chromatography into triglycerides, monogalactosyl diglycerides, steryl esters and esterified steryl glucosides. Methyl esters of the fatty acids found in these four lipids were prepared and analyzed by gas liquid chromatography. Each of the eight citrus varieties gave a series of four profiles which could be distinguished from the others. The Temple tangor has four profiles all showing a large percentage of linolenic acid. In all varieties steryl esters and to a lesser extent esterified steryl glucosides contain relatively large concentrations of 22∶0 to 26∶0 saturated acids. The profiles differ markedly from the patterns found for these four lipids in other higher plants studied. So. Market. Nutr. Res. Div., ARS, USDA.     

Lipids of the earthwormLumbricus terrestris

The lipid composition of the earthwormLumbricus terrestris has been reexamined under conditions intended to avoid enzymatic and chemical alterations during storage, extraction, and fractionation procedures. The simple lipids included aliphatic hydrocarbons, steryl esters, glycerides, and at least nine different sterols, all though to be derived from the diet. Free fatty acids, previously considered to be major components of worm lipids, comprised only 0.3% of the total lipid weight. Phospholipids included (in order of relative abundance) phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol, as well as sphingomyelin. Glycolipids included cerebrosides and sulfatides containing both glucose and galactose, and gangliosides containing glucosamine and sialic acid. The fatty acid compositions of these lipid classes appeared to be a mixture of what are considered typical plant, bacterial, and animal acids. Several fatty acids found in the worms, includingcis-vaccenic and eicosapentaenoic acids, were essentially absent from the dietary components, and it is concluded that these acids were synthesized in the worms. The earthworm derives much of its lipid adventitiously, but exerts at least some control over its tissue lipid composition.     

Thin layer chromatographic procedure for class separation of plant neutral lipids

A thin layer chromatographic method has been developed for the class separation of plant neutral lipids. Utilizing a two-step development in one dimension, lipid mixtures are separated into hydrocarbon waxes, steryl esters, methyl esters, triglycerides, fatty acids, diglycerides, sterols, and monoglycerides. The method may be employed for either qualitative or preparative purposes.     

Lipids of cultured hepatoma cells: VII. Structural analyses of glycerolipids in minimal deviation hepatoma 7288C

Phosphatidylcholine. phosphatidylethanolamine, and triglycerides were isolated from minimal deviation hepatoma 7288C cells cultured as monolayers to confluency in roller flasks containing Swim's 77 medium supplemented with 5% fetal calf serum, plus 20%, 10%, or 5% bovine serum. Fatty acid distribution at each position of glycerol was determined for the 3 glycerolipid classes, and carbon number distributions of triglycerides and diglycerides derived from phosphatidylcholine and phosphatidylethanolamine were quantitated by high temperature gas liquid chromatography. Fatty acid composition was only marginally affected by the level of bovine serum in the culture medium. Percentage composition of fatty acids esterified at each position of the 3 glycerolipids was different, indicating a nonrandom distribution of acyl groups in triglycerides and the 2 diacyl phosphatides. The carbon number distribution of diglycerides derived from phosphatidylcholine and phosphatidylethanolamine was different, and neither carbon number distribution agreed with the calculated 1-random, 2-random diacyl distribution, thus indicating pairing of certain acids in the diglycerides derived from these phospholipd classes. The determined triglyceride carbon number distributions did not show complete agreement with those calculated, assuming a 1-random, 2-random, 3-random type of fatty acyl distribution, suggesting preferential pairing of some acids in this lipid class. The 1-, 2-diglycerides derived from phosphatidylcholine, phosphatidylethanolamine, and triglycerides differed, indicating either selectivity in utilization of diglyceride species in biosynthesis of these glycerolipids, or modification of glycerolipids after their initial synthesis.     

Methodology for the separation o plant lipids and application to spinach leaf and chloroplast lamellae

Procedures for separation of complex plant lipids and results obtained are reviewed. Procedures based on DEAE cellulose and silicic acid chromatography, which may be preceded by countercurrent distribution, are presented for separation of the individual glyceroland sphingolipid classes of spinach leaf and chloroplast lamellae. These procedures appear to be generally applicable to photosynthetic tissue of plants and algae. The separation and infrared spectra of mono-and digalactosyl diglycerides, lecithin, phosphatidyl ethanolamine, phosphatidyl glycerol, phosphatidyl inositol, plant sulfolipid, cerebroside, and sterol glycosides from spinach are recorded. Chloroplast lamellae lipids are in the molar ratio monogalactosyl diglyceride (14.0), digalactosyl diglyceride (8.0), phosphatidyl glycerol (5.5), sulfolipid (3.9), lecithin (2.0), phosphatidyl inositol (1.0). Phosphatidyl ethanolamine, cerebrosides, and sterol glycosides were not detected in chloroplast lamellae. Fatty acid composition of individual lamellae lipids have been determined: The galactosyl lipids contain more than 90% trienoic acids.Trans-3- hexadecenoic acid is restricted almost exclusively to phosphatidyl glycerol. In this report techniques which have been applied to the isolation of plant glycero- and sphingolipids are reviewed and a new scheme presented for the separation of several of the plant lipid classes. Results obtained with spinach leaf and its photosynthetic apparatus are presented and discussed. Paper III in the series Plant and Chloroplast Lipids. Presented at the 15th Annual Summer Program, “Symposium on Quantitative Methodology in Lipid Research”, Aug. 3–7, 1964. Literature is reviewed to July 1964.     

Formation of diglycerides of long turnover time from labeled acetate and glucose in rat tissues

Rat adipose tissue pieces were incubated with acetate-2-¹⁴C and glucose-¹⁴C(U), respectively, and liver slices with acetate-2-¹⁴C. The labeled tissues were then reincubated in inactive medium, and the changes of radioactivity in the different lipid classes were determined. In all three experiments a significant amount of radioactivity was incorporated in the diglycerides. During 1 hr of reincubation in inactive medium the radioactivity of diglycerides decreased from 35 to 26% of the total lipid activity in the adipose tissue labeled with acetate. In the adipose tissue labeled with glucose radioactivity fell from 25 to 19%. In liver slices 11% of the labeled acetate was incorporated in the diglycerides, and during the 2 hr of reincubation this value fell to its half. The radioactivity of the uniformly labeled glucose was distributed equally in the fatty acids and the glycerol. The distribution of radioactive glycerol between diglycerides and triglycerides was similar to that of the labeled fatty acids. Triglyceride synthesis seems to always be accompanied by the formation of diglycerides with a lastint turnover time.     

Bitterness of Lipids

We have been able to demonstrate, that the hydrophobicity of the amino acid side chains is responsible for the bitterness of a peptide. Now we investigated lipids (and carbohydrates) in the following classes: Monoglycerides, diglycerides, phosphatides, lysophosphatides, monohydroxy fatty acids, dihydroxy fatty acids, trihydroxy fatty acids, monosaccharides, disaccharides. It was found that for lipids and carbohydrates the ratio from the number of the C-atoms of a molecule to the number of the hydroxyl groups called the R-values, gave a good indication as to whether the lipid or carbohydrate was sweet, bitter or non-bitter. For sweet compounds we found R = 1.00 - 1.99, for bitter compounds we found R =2.00 - 6.99, and for non-bitter compounds we found a value of R higher than 7.00. These results confirm our earlier assumption, that like in the case of peptides, the bitterness of lipids and carbohydrates is caused by a certain range of the hydrophobicity.     

Plastid Anionic Lipids Are Essential for the Development of Both Photosynthetic and Non-Photosynthetic Organs in Arabidopsis thaliana

The lipid bilayer matrix of the thylakoid membrane of cyanobacteria and chloroplasts of plants and algae is mainly composed of uncharged galactolipids, but also contains anionic lipids sulfoquinovosyldiacylglycerol (SQDG) and phosphatidylglycerol (PG) as major constituents. The necessity of PG for photosynthesis is evident in all photosynthetic organisms examined to date, whereas the requirement of SQDG varies with species. In plants, although PG and SQDG are also found in non-photosynthetic plastids, their importance for the growth and functions of non-photosynthetic organs remains unclear. In addition, plants synthesize another anionic lipid glucuronosyldiacylglycerol (GlcADG) during phosphorus starvation, but its role in plant cells is not elucidated yet. To understand the functional relationships among PG, SQDG, and GlcADG, we characterized several Arabidopsis thaliana mutants defective in biosynthesis of these lipids. The mutants completely lacking both PG and SQDG biosynthesis in plastids showed developmental defects of roots, hypocotyls, and embryos in addition to leaves, which suggests that these lipids are pleiotropically required for the development of both photosynthetic and non-photosynthetic organs. Furthermore, our analysis revealed that SQDG, but not GlcADG, is essential for complementing the role of PG, particularly in photosynthesis under PG-deficient conditions such as phosphorus starvation.     

Control of Plant Defense Mechanisms and Fire Blight Pathogenesis through the Regulation of 6‐Thioguanine Biosynthesis in Erwinia amylovora

Fire blight is a devastating disease of Rosaceae plants, such as apple and pear trees. It is characterized by necrosis of plant tissue, caused by the phytopathogenic bacterium Erwinia amylovora. The plant pathogen produces the well‐known antimetabolite 6‐thioguanine (6TG), which plays a key role in fire blight pathogenesis. Here we report that YcfR, a member of the LTTR family, is a major regulator of 6TG biosynthesis in E. amylovora. Inactivation of the regulator gene (ycfR) led to dramatically decreased 6TG production. Infection assays with apple plants (Malus domestica cultivar Holsteiner Cox) and cell cultures of Sorbus aucuparia (mountain ash, rowan) revealed abortive fire blight pathogenesis and reduced plant response (biphenyl and dibenzofuran phytoalexin production). In the presence of the ΔycfR mutant, apple trees were capable of activating the abscission machinery to remove infected tissue. In addition to unveiling the regulation of 6TG biosynthesis in a major plant pathogen, we demonstrate for the first time that this antimetabolite plays a pivotal role in dysregulating the plant response to infection.     

Threat at One End of the Plant: What Travels to Inform the Other Parts?

Adaptation and response to environmental changes require dynamic and fast information distribution within the plant body. If one part of a plant is exposed to stress, attacked by other organisms or exposed to any other kind of threat, the information travels to neighboring organs and even neighboring plants and activates appropriate responses. The information flow is mediated by fast-traveling small metabolites, hormones, proteins/peptides, RNAs or volatiles. Electric and hydraulic waves also participate in signal propagation. The signaling molecules move from one cell to the neighboring cell, via the plasmodesmata, through the apoplast, within the vascular tissue or—as volatiles—through the air. A threat-specific response in a systemic tissue probably requires a combination of different traveling compounds. The propagating signals must travel over long distances and multiple barriers, and the signal intensity declines with increasing distance. This requires permanent amplification processes, feedback loops and cross-talks among the different traveling molecules and probably a short-term memory, to refresh the propagation process. Recent studies show that volatiles activate defense responses in systemic tissues but also play important roles in the maintenance of the propagation of traveling signals within the plant. The distal organs can respond immediately to the systemic signals or memorize the threat information and respond faster and stronger when they are exposed again to the same or even another threat. Transmission and storage of information is accompanied by loss of specificity about the threat that activated the process. I summarize our knowledge about the proposed long-distance traveling compounds and discuss their possible connections.     

Lipids in the germ,endosperm and pericarp of the developing maize kernel

Acyl lipids were quantified in the germ, endosperm and pericarp of LG-11 maize kernels at eight stages of development from 9 to 87 days after pollination (DAP). Changes in the lipids are discussed in relation to morphological events in the developing kernel. Storage lipids (triglyceride, steryl ester) and membrane lipids (diacylphospholipids) accumulated in germ until 52-76 DAP, then decreased slightly without formation of lipid degradation products, lated in endosperm until 36-42 DAP and then decreased. Maximum values for galactosyldiglycerides and diacylphospholipids (nonstarch lipids) were reached at 16-23 DAP, and all decreased to very low values at maturity. Loss of these functional (membrane) lipids during the period of endosperm cell filling is unexpected. Starch contained 82% of the lysophospholipids and 64% of the free fatty acids in endosperm at 76 DAP. Endosperm lysophospholipids increased until 76 DAP and then decreased slightly, while free fatty acids increased continuously mostly inside starch granules at all stages of development, and any possible decrease after 76 DAP was masked by acids formed by hydrolysis of aleurone and endosperm nonstarch lipids from 52 DAP. In DAP, and phospholipids decreased after 42 DAP. Loss of these lipids is associated with senescence of most pericarp tissue. Triglycerides and steryl esters accumulated steadily to maturity, while the main accumulation of unsaponifiables occurred after 52 DAP about the time of suberin formation.     

Lipids of maturing grain of corn (Zea mays L.):

The polar lipids of a standard corn inbred, H51, were analyzed as the kernels developed. The concentrations of the glycolipids and phospholipids were highest at 30–45 days after pollination and then decreased. Digalactosyl diglyceride was the dominant glycolipid in the maturing grain. Monogalactosyl diglyceride and sulfolipid were also major sugar-containing lipids, but steryl glycoside ester, steryl glycoside and cerebrosides were relatively minor components. Phosphatidyl choline accounted for over 50% of the total phosphorus of the phospholipids at all stages of kernel development. Phosphatidyl ethanolamine and phosphatidyl inositol ranked second and third. Each individual lipid had its own characteristic fatty acid pattern, but the changes in fatty acid composition during development of the corn kernels were similar for all the lipids. The percentages of palmitic acid and linolenic acid decreased while those of oleic acid increased. Contribution from the Department of Agronomy, University of Illinois, and Crops Research Division, ARS, USDA.     

Diglycerides as a Stabilizer of the ß'-Crystal Form in Margarines and Fats

The possibility of using diglycerides as a β'-stabilizer in fats was studied both in lab-scale and in pilot plant equipment. The margarine studied was of table type and contained a high level of hydrogenated rapeseed oil with low content of erucic acid, LOBRA. A characteristic feature of this fat is its rapid transition to the stable β-form. After producing margarines with different amount of diglycerides the polymorphic transitions were followed by X-ray diffraction during storage. The results clearly show the potential of using diglycerides as a β'-stabilizer, which must be of technical interest.     

芳香油与油脂植物资源教学实践

精油与油脂分别是芳香油植物和油脂植物提取的天然产品.通过芳香油与油脂植物资源教学实践,探求植物资源学课程适宜的教学内容与方法.从专业特色角度出发,除了讲授常规植物资源总论和植物资源各论,增加了森林植物资源学和植物资源学课内实践（实验）等相关内容,加强学生实践技能培养,提升本科生综合素质.     

Plant Dependence on Rhizobia for Nitrogen Influences Induced Plant Defenses and Herbivore Performance

Symbiotic rhizobia induce many changes in legumes that could affect aboveground interactions with herbivores. We explored how changing the intensity of Bradyrhizobium japonicum, as modulated by soil nitrogen (N) levels, influenced the interaction between soybean (Glycine max) and herbivores of different feeding guilds. When we employed a range of fertilizer applications to manipulate soil N, plants primarily dependent on rhizobia for N exhibited increased root nodulation and higher levels of foliar ureides than plants given N fertilizer; yet all treatments maintained similar total N levels. Soybean podworm (Helicoverpa zea) larvae grew best on plants with the highest levels of rhizobia but, somewhat surprisingly, preferred to feed on high-N-fertilized plants when given a choice. Induction of the defense signaling compound jasmonic acid (JA) by H. zea feeding damage was highest in plants primarily dependent on rhizobia. Differences in rhizobial dependency on soybean did not appear to affect interactions with the phloem-feeding soybean aphid (Aphis glycines). Overall, our results suggest that rhizobia association can affect plant nutritional quality and the induction of defense signaling pathways and that these effects may influence herbivore feeding preferences and performance—though such effects may vary considerably for different classes of herbivores.     

植物次级代谢物的多样性及其在细胞培养中的调控研究进展

介绍了一个有趣的植物细胞次级代谢物多样性的课题，综述了植物细胞培养中次级代谢产物多样性的调控。作为典型事例，特别对三七细胞培养中诱导荆如何影响皂苷的生物合成，结合本实验室的最近研究结果，进行了阐述；并就诱导剂在信号传导途径中的作用进行了探讨。无疑这样的多学科交叉研究是当今生物化工学科的发展趋势。     

Plant Cell Wall Proteomes: The Core of Conserved Protein Families and the Case of Non-Canonical Proteins

Plant cell wall proteins (CWPs) play critical roles during plant development and in response to stresses. Proteomics has revealed their great diversity. With nearly 1000 identified CWPs, the Arabidopsis thaliana cell wall proteome is the best described to date and it covers the main plant organs and cell suspension cultures. Other monocot and dicot plants have been studied as well as bryophytes, such as Physcomitrella patens and Marchantia polymorpha. Although these proteomes were obtained using various flowcharts, they can be searched for the presence of members of a given protein family. Thereby, a core cell wall proteome which does not pretend to be exhaustive, yet could be defined. It comprises: (i) glycoside hydrolases and pectin methyl esterases, (ii) class III peroxidases, (iii) Asp, Ser and Cys proteases, (iv) non-specific lipid transfer proteins, (v) fasciclin arabinogalactan proteins, (vi) purple acid phosphatases and (vii) thaumatins. All the conserved CWP families could represent a set of house-keeping CWPs critical for either the maintenance of the basic cell wall functions, allowing immediate response to environmental stresses or both. Besides, the presence of non-canonical proteins devoid of a predicted signal peptide in cell wall proteomes is discussed in relation to the possible existence of alternative secretion pathways.     

Flexibility Potential of Photovoltaic Power Plant and Biogas Plant Hybrid Systems in the Distribution Grid

The potential of combining biogas and photovoltaic (PV) power plants in hybrid systems in the German distribution grid is analyzed. The focus of the present research is on balancing the intermittent power supply from PV power plants with the controllable power production of combined heat and power (CHP) units of biogas plants within a period of seconds. To achieve an increase of the total energy feed-in of biogas and PV power plants to the electricity grid, a biogas plant energy management system is described. System parameters, such as the variable feed-in of PV power plants or power ramps of the start-up process of controllable biogas plant CHP unit, are described and adapted to the global installed capacity of PV power plant and biogas plants in the German distribution grid.     

The distribution of cyclopropane and cyclopropene fatty acids in higher plants (Malvaceae)

The occurrence and distribution of cyclopropane and cyclopropene fatty acids has been investigated in seeds, leaves and other tissues of several species of Malvaceae. Sterculic and malvalic acids and their dihydro-analogs were present in all the plant tissues examined, the highest proportions generally being in immature seeds. The cyclic acids were mainly concentrated in the neutral lipids with lesser proportions in phospholipid or glycolipid classes. The occurrence of these acids in all tissues of some species offered the attractive possibility of establishing callus tissue cultures capable of synthesizing cyclopropane and cyclopropene fatty acids and thereby providing a more convenient and reproducible system for biosynthetic studies. Substantial proportions of these cyclic acids were found in callus tissue cultures propagated from twoMalva species.