Digalactosyl Diglyceride Research Articles

Analysis of lipid composition of cell-bound membrane vesicles (CBMVs) derived from endothelial cells

Cell-bound membrane vesicles (CBMVs), a novel type of membrane vesicles, have been identified through a series of characterization tools. However, the lipid composition of CBMVs has not yet been characterized. This study focuses on the differences in lipid composition between CBMVs and cell membranes. In order to determine the lipid composition of CBMVs and cell membranes of Human umbilical vein endothelial cells (HUVECs) and find out differential metabolites, this study was carried out by isolating CBMVs lipids and characterizing them using high-performance liquid chromatography tandem secondary mass spectrometry (LC-MS/MS). The results showed the presence of 213 up-regulated and 726 down-regulated lipids in CBMVs compared to cell membranes which produced CBMVs. There are lipids expressed in CBMVs and not in cell membranes: DGDG 18:0_8:0, DGDG O-8:0_16:1, DGDG O-26:7_26:7, DGDG O-16:3_26:7, TG 15:4_21:5_22:5; 4O, PC 49:11, PG 19:5_38:10, PI 60:14, PI 44:9, PI 25:2, PI 43:5, PI 50:10, PS 55:10. DGDG (digalactosyl diglyceride), MGDG (monogalactosyl diglyceride) belongs to galactosyl diglyceride, promotes fat catabolism, which also has antioxidant and anti-inflammatory effects, and unsaturated diacylglycerols are a class of antioxidant compounds, which enables CBMVs to have a therapeutic potential.

Genetic variation in wheat grain quality is associated with differences in the galactolipid content of flour and the gas bubble properties of dough liquor

Lipids affect the quality of wheat flour for breadmaking. One possible mechanism is stabilization of the gas cells which are formed during dough mixing and expanded during fermentation, leading to a greater loaf volume and evenness of texture. We therefore compared the lipidomic profiles of flour and dough liquor fractions (which contain surface-active components present at the gas bubble interface) from two sets of wheat lines differing in allelic variation at a QTL for loaf volume. Analyses of fractions from three field trials showed consistent increases in the contents of galactolipids (monogalactosyl diglyceride and digalactosyl diglyceride) in flour and dough liquor of the lines with the increasing (good quality) allele. Biophysical analysis showed that this was associated with greater elasticity of the dough liquor fraction. This is consistent with published studies reporting a relationship between galactolipids and breadmaking quality and suggests a mechanism of action for the QTL.

The Serine Carboxypeptidase-Like Gene SCPL41 Negatively Regulates Membrane Lipid Metabolism in Arabidopsis thaliana.

The Arabidopsis has 51 proteins annotated as serine carboxypeptidase-like (SCPL) enzymes. Although biochemical and cellular characterization indicates SCPLs involved in protein turnover or processing, little is known about their roles in plant metabolism. In this study, we identified an Arabidopsis mutant, bis4 (1-butanol insensitive 4), that was insensitive to the inhibitory effect of 1-butanol on seed germination. We cloned the gene that was defective in bis4 and found that it encoded an SCPL41 protein. Transgenic Arabidopsis plants constitutively expressing SCPL41 were generated, oil body staining and lipidomic assays indicated that SCPL41-overexpressing plants showed a decrease in membrane lipid content, especially digalactosyl diglyceride (DGDG) and monogalactosyl diglyceride (MGDG) contents, while the loss of SCPL41 increased the membrane lipid levels compared with those in wild-type plants. These findings suggested that SCPL41 had acquired novel functions in membrane lipid metabolism.

Structure of the plant photosystem I.

Plant photosystem I (PSI) is one of the most intricate membrane complexes in nature. It comprises two complexes, a reaction center and light-harvesting complex (LHC), which together form the PSI-LHC supercomplex. The crystal structure of plant PSI was solved with two distinct crystal forms. The first, crystallized at pH 6.5, exhibited P21 symmetry; the second, crystallized at pH 8.5, exhibited P212121 symmetry. The surfaces involved in binding plastocyanin and ferredoxin are identical in both forms. The crystal structure at 2.6 Å resolution revealed 16 subunits, 45 transmembrane helices, and 232 prosthetic groups, including 143 chlorophyll a, 13 chlorophyll b, 27 β-carotene, 7 lutein, 2 xanthophyll, 1 zeaxanthin, 20 monogalactosyl diglyceride, 7 phosphatidyl diglyceride, 5 digalactosyl diglyceride, 2 calcium ions, 2 phylloquinone, and 3 iron sulfur clusters. The model reveals detailed interactions, providing mechanisms for excitation energy transfer and its modulation in one of nature's most efficient photochemical machine.

Improving Skin Hydration and Age-related Symptoms by Oral Administration of Wheat Glucosylceramides and Digalactosyl Diglycerides: A Human Clinical Study

Ceramides are known to play a key role in the skin’s barrier function. An age-dependent decrease in ceramides content correlates with cutaneous clinical signs of dryness, loss of elasticity, and increased roughness. The present placebo-controlled clinical study aims to evaluate if an oral supplementation with glucosylceramides (GluCers) contained in a wheat polar lipids complex (WPLC) was able to improve such skin conditions. Sixty volunteers presenting dry and wrinkled skin were supplemented during 60 days with either a placebo or a WPLC extract in oil or powder form (1.7 mg GluCers and 11.5 mg of digalactosyldiglycerides (DGDG)). Skin parameters were evaluated at baseline and after 15, 30, and 60 days of supplementation. Oral intake of WPLC significantly increased skin hydration (p < 0.001), elasticity, and smoothness (p < 0.001), and decreased trans epidermal water loss (TEWL) (p < 0.001), roughness (p < 0.001), and wrinkledness (p < 0.001) in both WPLC groups compared to placebo. In both WPLC treated groups, all parameters were significantly improved in a time-dependent manner compared to baseline. In conclusion, this study demonstrates the positive effect of oral supplementation with GluCers on skin parameters and could reasonably reinforce the observations made on mice that orally-supplied sphingolipids can reach the skin.

A novel approach based on untargeted lipidomics reveals differences in the lipid pattern among durum and common wheat

In the present work the possibility of using an untargeted metabolomic strategy to discriminate between common and durum wheat lipidome for an authenticity purpose was explored. A first study was conducted by analyzing 52 samples from two durum and common wheat varieties. Afterwards, an extended and independent sample set (173 samples and five varieties) was used as a confirmatory study to verify the stability and consistency of the models obtained. Putatively identified markers were evaluated applying ROC curves resulting in individual marker AUC >90% both in preliminary and confirmatory study. In addition, digalactosyl diglyceride (DGDG) 36:4 was shown to be an effective marker differentiating between authentic durum wheat and its adulterated admixture down to 3% adulteration level, which is the maximum contamination level allowed by Italian legislation. The results demonstrated that untargeted lipidomics, in conjunction with chemometric tools has a significant potential for screening and detection of wheat fraud.

Relationships between lipase-treated wheat lipid classes and their functional effects in wheat breadmaking

Fractionation of lipase-treated wheat lipids showed that polar lipase-reaction products were responsible for their positive functional effects in breadmaking. The results allowed the conclusion that an optimal baking lipase preferably hydrolyzes monogalactosyl diglycerides and N-acyl phosphatidyl ethanolamine, but has only moderate activity towards digalactosyl diglycerides. Synergistic effects of digalactosyl diglycerides and their products digalactosyl monoglycerides (molar proportion 1:1) provide even a greater bread volume increase. Reconstitution baking (defatted flour plus lipid or lipid fraction added) partly provided contradictory results. 100% polar lipase-treated lipids were less active than untreated polar dough lipids plus polar flour lipids. Combinations of non-polar and polar lipase-treated lipids were even more active than the polar ones alone. It appears that the polar reaction products of baking lipases need the presence of unmodified lipids or non-polar lipids to provide optimal functional effects. The present data suggests that synergistic effects between different lipid classes might play a key role in the mechanism of action of baking lipases.

Anti-herpes simplex virus activities of monogalactosyl diglyceride and digalactosyl diglyceride from Clinacanthus nutans, a traditional Thai herbal medicine

ObjectiveTo evaluate the monogalactosyl diglyceride (MGDG) and digalactosyl diglyceride (DGDG) from Clinacanthus nutans (C. nutans) for their in vitro antiviral activities against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) by plaque reduction assay. MethodsMGDG and DGDG were extracted with chloroform from C. nutans leaves. MGDG and DGDG were separated from chloroform crude extract using column chromatography, characterized by thin layer chromatography and quantified by high performance liquid chromatography. The anti HSV-1 and 2 activity against pre-treatment and post-treatment of the compounds was evaluated using plaque reduction assay. The cytotoxicity of the extract and the compounds on Vero cells were performed by MTT assay. ResultsMGDG and DGDG obtained by column chromatography showed identical profiles as standard MGDG and standard DGDG using thin layer chromatography and high performance liquid chromatography. MGDG and DGDG from C. nutans showed 100% inhibition of HSV-1 replication at the post step of infection at noncytotoxic concentration with IC50 values of 36.00 and 40.00 μg/mL, and HSV-2 at 41.00 and 43.20 μg/mL, respectively. Moreover, MGDG and DGDG from C. nutans were demonstrated to have anti-herpes simplex activity at the same level as standard synthetic compounds. In contrast, pre-treatment of Vero cells with MGDG and DGDG before HSV-1 and HSV-2 infection did not show inhibitory effect against these viruses. MGDG and DGDG exhibited antiviral activity against HSV-1 with selectivity index of 26.00 and 23.00 and HSV-2 of 23.30 and 21.30. ConclusionsMGDG and DGDG from C. nutans, a traditional Thai herbal medicine illustrated inhibitory activity against HSV-1 and HSV-2, probably by inhibiting the late stage of multiplication, suggesting their promising use as anti-HSV agents.

Composition and Antiradical Power of Syzygium aromaticum Lipids

2) determine the total phenolic content and in vitro radical scavenging activity of CO. The results from the present study will be used to develop novel edible oil products rich in bioactive molecules with a desirable shelf life. The proportion of lipid classes present in CO as well as the R f values of the subclasses are shown in Table 1. The level of NL was the highest (ca. 94.7%), followed by GL (0.76%) and PL (0.39%). The data are in agreement with Suzuki et al. [13] who analyzed the lipid classes of clove lipidic extract. Subclasses of NL contained triacylglycerol (TG), free fatty acids (FFA), diacylglycerol (DG), esterified sterols (STE), and monoacylglycerol (MG) in decreasing order. A significant amount of TG was found (ca. 96.6% of total NL) followed by a relatively low level of FFA (ca. 1.4% of total NL), while DG and STE were recovered in lower levels. The subclasses of GL found in CO were sulfoquinovosyl diacylglycerol (SQD), digalactosyl diglycerides (DGD), cerebrosides (CER), steryl glycosides (SG), monogalactosyl diglycerides (MGD), and esterified steryl glycosides (ESG) as presented in Table 1. The proportion of each component was estimated by lipid-carbohydrate determination. CER, SG, and ESG were the prevalent components and made up about 92% of the total GL. The PL subclasses in CO were separated into four major fractions via TLC. The TLC fractions of PL revealed that the predominant PL subclasses were PC followed by PE, PI, and PS (Table 1). About half of the total PL was in PC and a quarter was in PE, while PI and PS were isolated in smaller quantities. The fatty acid profiles of CO and lipid classes (NL, GL, and PL) are presented in Table 2. According to the results, nine fatty acids were identified in CO. Linoleic and oleic acids were the main fatty acids in CO. Both fatty acids comprise together about 80% of the total FAME. The cold-pressed oil contained significant levels of monounsaturated fatty acids (MUFA, 39.7 g/100 g total fatty acids), which is comparable to cold pressed hemp, cranberry, blueberry, onion, and milk thistle seed oils but is much lower than the 81 and 82% in carrot and parsley cold pressed seed oils 14, 15.

Effect of plant growth temperature on membrane lipids in strawberry ( Fragaria × ananassa Duch.)

Changes in membrane lipid composition are important in the acclimation of plants. The influence of four day/night growing temperature combinations (18/12, 25/12, 25/22, and 30/22 °C) on membrane lipids of ‘Earliglow’ and ‘Kent’ strawberry ( Fragaria × ananassa Duch.) were studied. The monogalactosyl diglyceride (MGDG) and digalactosyl diglyceride (DGDG) were the major galactolipids in the strawberry leaves. ‘Earliglow’ contained a higher amount of galactolipids in the leaves than ‘Kent’. The major phospholipids in the strawberry leaves, roots, and fruit were phosphatidylcholine (PC), phosphatidylinositol (PI), phosphatidylglycerol (PG), and phosphatidylethanolamine (PE). PC and PE were the two predominant phospholipids in the strawberry. The leaves and fruit of ‘Earliglow’ contained higher amounts of phospholipids compared to those of ‘Kent’, whereas ‘Kent’ strawberry roots had higher phospholipids. Palmitic (C16:0), stearic (C18:0), oleic (C18:1), linoleic (C18:2), and α-linolenic (C18:3) acids were major fatty acids in galacto- and phospholipids of the ‘Earliglow’ and ‘Kent’ strawberry. PC is very rich in linolenic acid in leaves compared to the fruit and root tissues. PC had the highest ratio of unsaturated to saturated fatty acids among all phospholipids. There was a significant increase in the content of galactolipids (MGDG, DGDG) and phospholipids (PC, PI, PG and PE) and unsaturation of their fatty acids in the cool day/night growth temperature. Increasing day/night growth temperatures decreased MGDG/DGDG ratios. The shifts in saturation and composition of fatty acids observed with strawberry may be an adaptation response of plants to the temperature changes.

Membrane degradation, accumulation of Phosphatidic acid, stimulation of catalase activity and nuclear DNA fragmentation during 2,4-d-induced leaf senescence in mustard

We investigated 2,4-D-induced leaf senescence in young mustard seedlings. A set of morphometric, biochemical and molecular parameters were analyzed to characterize senescence markers. In accordance with earlier reports, chloroplast-membrane degradation marked the early phase of leaf senescence based on the analysis of the galactolipid fraction. Degradation of grana occurred earlier to that of the envelope, as revealed by the relative level of their specific galactolipids, namely, monogalactosyl diglyceride and digalactosyl diglyceride. Phospholipids showed extensive degradation resulting in the accumulation of lyso-derivatives of major phospholipids and phosphatidic acid (PA) in senescing leaves. Catalase activity was stimulated by 2,4-D and reflected scavenging of reactive oxygen species. Nuclear DNA degradation, a previously known death signal that represented a point of no return from progression of senescence, occurred late on the 4th day subsequent to 2,4-D supplementation. AgNO3, an inhibitor of ethylene biosynthesis, inhibited leaf senescence by ca. 54% based on PA content Involvement of 2,4-D, ethylene and abscisic acid in leaf senescence is discussed in relation to hormonal interplay.

Efficient Gene Delivery with Serum into Human Cancer Cells Using Targeted Anionic Liposomes

Success of human gene therapy depends upon the development of delivery vehicles or vectors, which can selectively deliver therapeutic genes to target cells with efficiency and safety. Previous studies have shown an efficient, systemic trans-gene expression in many cell lines (in vitro) by using an anionic liposomal vector, based on the composition of retroviral envelopes (artificial viral envelopes, AVEs). The AVE-liposomes and their complexes with plasmid (DNA) were characterized according to zeta potential measurements and transmission electron microscopy (TEM). We successfully demonstrated that AVE liposomes, dispersed in 10% serum-containing growth medium, efficiently delivered plasmid DNA to HuH-7 (human hepatoma cell line) cells. We assessed the utility of liver-targeted vesicles as a drug/gene delivery system for the treatment of liver diseases. We found that small unilamellar AVE vesicles containing 15 mol% digalactosyl diglyceride (DGDG) are efficiently targeted to the liver via the hepatic asialoglycoprotein receptor.

A simple method for in vivo labelling of lipid fractions in developing seeds of Brassica campestris L

An in vivo method of labelling lipid fractions in developing seeds of Brassica campestris using [1–14C] acetate has been developed. The “wick” method for introducing label into the intact plant is quite effective, safe and easy to use. The results obtained were reproducible and comparable to those reported earlier for seeds procured from greenhouse grown plants. The labelling pattern showed that rapid oil deposition began around 20 days after anthesis (DAA) and continued until about 45 DAA. The proportion of label in polar lipids declined and that in non-polar lipids increased during the phase of active oil synthesis. Among phospholipids, the label was incorporated mainly in phosphatidyl choline (PC), which was found to be the major fraction of phospholipids. During development, the two galactolipids i.e. monogalactosyl diglyceride (MGDG) and digalactosyl diglyceride (DGDG) followed patterns exactly opposite to each other. The content of the label in MGDG decreased, while that in DGDG increased, indicating the conversion of MGDG to DGDG during maturation.

(R)-3-hydroxybutyrate dehydrogenase: selective phosphatidylcholine binding by the C-terminal domain.

(R)-3-Hydroxybutyrate dehydrogenase (BDH) is a lipid-requiring mitochondrial enzyme that has a specific requirement of phosphatidylcholine (PC) for function. The C-terminal domain (CTBDH) of human heart BDH (residues 195-297) has now been expressed in Escherichia coli as a chimera with a soluble protein, glutathione S-transferase (GST), yielding GST-CTBDH, a novel fusion protein that has been purified and shown to selectively bind to PC vesicles. Both recombinant human heart BDH (HH-Histag-BDH) and GST-CTBDH (but not GST) form well-defined protein-lipid complexes with either PC or phosphatidylethanolamine (PE)/diphosphatidylglycerol (DPG) vesicles (but not with digalactosyl diglyceride vesicles) as demonstrated by flotation in sucrose gradients. The protein-PC complexes are stable to 0.5 M NaCl, but complexes of either HH-Histag-BDH or GST-CTBDH with PE/DPG vesicles are dissociated by salt treatment. Thrombin cleavage of GST-CTBDH, either before or after reconstitution with PC vesicles, yields CTBDH (12 111 Da by MALDI mass spectrometry) which retains lipid binding without attached GST. The BDH activator, 1-palmitoyl-2-(1-pyrenyl)decanoyl-PC (pyrenyl-PC), at <2.5% of total phospholipid in vesicles, efficiently quenches a fraction (0.36 and 0.47, respectively) of the tryptophan fluorescence of both HH-Histag-BDH and GST-CTBDH with effective Stern-Volmer quenching constants, (K(Q))(eff), of 11 and 9.3 (%)(-)(1), respectively (half-maximal quenching at approximately 0.1% pyrenyl-PC). Maximal quenching by pyrenyl-PC obtains at approximately stoichiometric pyrenyl-PC to protein ratios, reflecting high-affinity interaction of pyrenyl-PC with both HH-Histag-BDH and GST-CTBDH. The analogous pyrenyl-PE effects a similar maximal quenching of tryptophan fluorescence for both proteins but with approximately 15-fold lower (K(Q))(eff) (half-maximal quenching at approximately 1.5% pyrenyl-PE) referable to nonspecific interaction of pyrenyl-PE with HH-Histag-BDH or GST-CTBDH. Thus, the 103-residue CTBDH constitutes a PC-selective lipid binding domain of the PC-requiring BDH.

Methyl Jasmonate Reduces Water Stress in Strawberry.

The effect of methyl jasmonate (MJ) on changes of oxygen-scavenging enzyme activities and membrane lipid composition was studied in strawberry leaves under water stress. Under water stress, MJ treatment reduced the increase of peroxidase (EC 1.11.1.7; POD) activity, maintained higher catalase (EC 1.11.1.6; CAT) and superoxide dismutase (EC 1.15.1.1; SOD) activities, and ascorbic acid content. In addition, MJ treatment reduced transpiration and membrane-lipid peroxidation as expressed by malondialdehyde (MDA) content, lessened the reduction of membrane lipids, glycolipids [monogalactosyl diglyceride (MGDG), digalactosyl diglyceride (DGDG)], and phospholipids [phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and phosphatidylinositol (PI)]. In water-deficit conditions, MJ treatment also alleviated the decline in the degree of fatty acid unsaturation and the ratio of linolenic (18:3) to linoleic acid (18:2). These results indicate that MJ treatment appears to alter the metabolism of strawberry plants rendering the tissue better able to withstand water stress.

Properties of digestive glycosidases and peptidases and the permeability of the peritrophic membranes of Abracris flavolineata (Orthoptera: Acrididae)

In Abracris flavolineata midguts, cellulose is hydrolyzed by at least three enzymes, whereas the most active hemicellulases are a laminarinase (pH optimum 5.7, M r 146 k) and three lichenases (pH optima in the range 5–7.3; M r values: 22, 71, and 97 k). Digestion of hemicellulose is completed by β-glucosidases described elsewhere and by an α-mannosidase (pH optimum 4.7, K m 1.7 mM). There are a major and two minor amylases (pH optimum 6.5; M r values: 42, 45, and 108 k) activated by chloride. Two of the α-glucosidases ( M r 74 and 94 k) are active on maltose and hence should finish the digestion of starch. It is not clear what is the natural substrate of the remaining α-glucosidase ( M r 93 k). The major α-galactosidase ( M r 112 k) is active on melibiose and raffinose, whereas the minor ( M r 70k) may be active on digalactosyl diglycerides. The effect of pH on azocasein hydrolysis and electrophoresis data suggest that trypsin is a major and chymotrypsin and cysteine proteinase are minor enzymes. The cysteine proteinase may derive from the leaves ingested by the grasshopper, taking into account its activity in leaves. Protein digestion is finished by two soluble aminopeptidases ( M r 92 and 105 k), a major membrane-bound aminopeptidase ( M r 97 k) and two membrane-bound dipeptidases ( M r 87 k). The sizes of the digestive enzymes recovered in A. flavolineata crops suggest that the pores of the semi-fluid caecal peritrophic membrane have diameters larger than 8.6 nm.

Mechanical properties of model membranes studied from shape transformations of giant vesicles

Membrane deformations occur frequently in cell functioning. From the physical point of view, the understanding of such shape changes requires the introduction of mechanical parameters like bending elasticity. In this article it is shown how this physical property can be obtained from the analysis of small or large shape transformations from giant vesicles. Then it is demonstrated that the bending modulus is strongly dependent on the membrane composition and environmental conditions. This is the case for one-component bilayers (dilauroylphosphatidylcholine (DLPC), dimyristoylphosphatidylcholine (DMPC), dipalmitoylphosphatidylcholine and stearoyloleoylphosphatidylcholine (SOPC)) and for two-component lipid mixtures (DMPC/cholesterol, DLPC/dilauroylphosphatidic acid). Further it is shown that the bending elasticity of natural lipid extracts (egg phosphatidylcholine, digalactosyl diglyceride and red blood cell lipid extracts) is generally smaller than that of comparable synthetic model membranes. The role of transmembrane proteins is examined by measuring the bending elasticity of SOPC/gramicidin mixtures. Finally, larger scale shape transformations of giant vesicles under an alternative electric field are discussed.

Environmental factors and genotypic changes in lipids contribute to the winter hardiness of Norway spruce (Picea abies).

Lipids were extracted from needles of Norway spruce plants of different provenances. The plants, seeds of which were originally collected from all over Europe, were grown at two sites in England at the same longitude but one 350 km north of the other. Significant correlations were observed between monogalactosyl diglyceride (MGDG) and digalactosyl diglyceride (DGDG) ratios on the one hand and, on the other, the lowest extreme winter temperature at the original site of seed collection (EWTS). In the case of lipid changes, however, environmental differences due to site were more important than the inherent genotypic characteristics of the planted trees while provenances with the lowest EWTS values had more MGDG than DGDG. This implies that existing winter hardiness under mild climatic conditions does not come from changes in this ratio although DGDG formation from MGDG is known to be an important feature of winter hardening in Norway spruce elsewhere in Europe. However, closer analysis of the fatty acids in lipids from provenances at individual sites did reveal significant correlations between those provenances with low EWTS values and certain molar amounts or ratios of fatty acids in DGDG, some of which could be traced to genotypic expression. These partly involved the unusual Δ5 desaturations which are mainly confined to the fatty acids of those conifers like Norway spruce that harden to very low temperatures.

カンキツ葉における脂質組成とその季節的変動

Seasonal changes of lipid compositions in leaves of Natsudaidai 'Kawanonatsudaidai' (Citrus natsudaidai Hayata), a cold-sensitive species, and Yuzu 'Tadanishiki' (Citrus junos sieb. ex Tanaka), a frost-hardy species, were studied.Glycolipids were mainly monogalactosyl diglyceride (MGDG) and digalactosyl diglyceride (DGDG), whereas the phospholipids were mainly phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylglycerol (PG). The main fatty acids in both lipids were palmitic acid (16 : 0), stearic acid (18 : 0), oleic acid (18 : 1), linoleic acid (18 : 2), and linolenic acid (18 : 3). PG contained trans-Δ3-hexadecenic acid (16 : 1).PG was less unsaturated phospholipid than were PC and PE, whereas MGDG was more unsaturated than was DGDG.Phospholipid levels (PC and PE) were high during winter in Natsudaidai and Yuzu. The 18 : 3 and 18 : 2 compositions in glycolipid (MGDG) increased and the double bond index (D. B. I.) attained a high level in winter. The 18 : 2 and 18 : 3 compositions in phospholipid (PC) increased and D. B. I. approached maximum during winter. Phospholipid contents and 18 : 3 compositions in glycolipid (MGDG) and phospholipid (PC) were higher in Yuzu than they were in Natsudaidai.Sterol contents increased during winter concomitantly with phospholipid and β-sitosterol; the sterols were higher in Yuzu than in Natsudaidai.

Changes in Lipid Composition of Brassica Siliquae Upon Infection by Cuscuta

Summary Infection of Indian rape (Brassica campestris) cv. Sarson- T42 by the shoot parasite, Cuscuta, initiated at 24 days after sowing (DAS), was more effective than that initiated at a later stage of the development of the host plant. Studies carried out on siliqua chloroplasts of rape plant showed an 83% increase in neutral lipids (pigments and free fatty acids) with a decrease in glycolipid and phospholipid contents by 19 and 34%, respectively. The content of monogalactosyl diglyceride (MGDG) and digalactosyl diglyceride (DGDG) was reduced significantly without a change in the MGDG/DGDG ratio. At 62 DAS, the chlorophyll content of siliqua chloroplasts had decreased by about 21, 18 and 15% when infection by Cuscuta was initiated, respectively at 24, 31 and 38 DAS. The carotenoid content, on the other hand, increased significantly upon infection. A significant increase was observed in all the saturated fatty acids, while unsaturated fatty acids, especially linoleic and linolenic acids, decreased significantly upon infection initiated at 24 DAS. The decrease in unsaturation was 22% upon infection initiated at 24 DAS and became negligible when initiated at 52 DAS. Thus, the severity of damage induced by Cuscuta to rape siliquae was dependent on the developmental stage of host plant at the time of infection.