Polar Lipid Composition Research Articles

Haloarcula amylolytica sp. nov., an extremely halophilic archaeon isolated from Aibi salt lake in Xin-Jiang, China

A starch-hydrolysing and extremely halophilic archaeon (strain BD-3(T)), isolated from Aibi salt lake in Xin-Jiang, China, was characterized phenotypically and genotypically in order to determine its taxonomic status. On the basis of its polar lipid composition, nucleotide sequences of its 16S rRNA genes, genomic DNA G+C content (62.4 mol%) and growth characteristics, the organism could be assigned to the genus Haloarcula. Phenotypic differences and low DNA-DNA hybridization values to related Haloarcula species distinguished strain BD-3(T) from recognized Haloarcula species. It is therefore concluded that strain BD-3(T) represents a novel species, for which the name Haloarcula amylolytica sp. nov. is proposed. The type strain is BD-3(T) (=CGMCC 1.5335(T)=JCM 13557(T)).

超好熱硫酸還元古細菌<i>Archaeoglobus fulgidus</i>の脂質部品分析

Archaeoglobus (A.) fulgidus is a hyperthermophilic, anaerobic, sulfate-reducing archaeon. Although the polar lipid composition of various archaea has been reported, no information has been available for A. fulgidus polar lipids. The present paper reports the results of lipid component parts analysis applied to the archaeon. Lipid component parts analysis is a simplified analytical method developed by the authors to obtain a rough outline of information about the polar lipid of a species of a microorganism. Unfractionated total lipid is subjected to several chemical degradation procedures to release lipid component parts (core lipids, glycolipid sugars and phospholipid polar head groups), which are identified by appropriate chromatography. Archaeol and caldarchaeol were found as core lipids along with an unknown core lipid. The major glycolipid sugars were galactose and mannose. A trace amount of glucose was also detected. The phosphodiester-linked polar head groups of phospholipids were inositol and ethanolamine. The presence of these lipid components is consistent with the occurrence of polar lipid-synthesizing enzymes detected by a BLAST search of the whole genome sequence of the organism. An amino group containing phospholipid was found for the first time in an archaeon other than methanogenic archaea.

Lipolytic and oxidative changes in Iberian dry-cured loin

This study was conducted using 61 Iberian pigs from four different genetic lines fattened under two different rearing systems. Fatty acid composition of neutral lipids (NL), polar lipids (PL) and free fatty acids (FFA) of the 61 fresh loins and their corresponding dry-cured loins and indices of lipid oxidation (hexanal, TBARS and rancid flavour) of the dry-cured loins were analyzed. Although the total amount of fatty acids from PL decreased most (89.77%), the fatty acid profile of FFA from dry-cured loin was more similar to that of NL from fresh loins. Monounsaturated fatty acids (MUFA) were the most abundant FFA type (260 mg/100 g muscle dry matter) followed by saturated fatty acid (SFA) (256 mg/100 g muscle dry matter) and polyunsaturated fatty acids (PUFA) (148 mg/100 g muscle dry matter). Neither genetic line nor rearing system showed any significant ( P > 0.05) effect on the decrease of fatty acids in the lipid fractions studied. The important decrease in PUFA from NL (43.70%) and PL (89%) was not reflected in higher oxidative indices in dry-cured loin. Neither PCA nor Pearson’s correlation showed any clear relationships between lipolytic changes and oxidative indices.

The effects of a weak permanent magnetic field on the lipid composition and content in the onion leaves of various ages

We have studied the effects of a weak permanent magnetic field (PMF) with strength of 403 A/m on the composition and content of polar and neutral lipids and the composition of their fatty acids (FAs). The lipids were isolated from the third, fourth, and fifth leaves of onion (Allium cepa L., cv. Arzamasskii) plants, and their composition was determined using TLC and GLC techniques. Plants growth under the conditions of a natural geomagnetic field served as a control. Most intense changes in the lipid content induced by PMF were observed in the fourth onion leaf. The content of total lipids and that of polar lipids (glyco-and phospholipids) changed, whereas the content of neutral lipids either decreased or remained unchanged. The phospholipid/sterol ratio increased, causing an increase in the fluidity of the membrane lipid bilayer. PMF induced an increase in the concentration of linolenic acid and the relative content of total unsaturated FAs. The effects of PMF on the content and composition of lipids in the third and fifth onion leaves were less pronounced, demonstrating differences between the leaves of various ages in their sensitivity to the effects of magnetic field. It is concluded that changes in the weak PMF within the limits of changes in the strength of geomagnetic field in the course of evolution can affect biochemical and physiological processes of plants.

The isolation and structure of membrane lipid rafts from rat brain

The action of detergents in the isolation of detergent-resistant membrane fractions from rat brain is reported. Triton X-100 treatment of whole rat brain homogenate at 4 °C produced detergent-resistant membranes with a density of 1.07 g/ml compared with Brij96 where the density of the membrane was only 1.05 g/ml. The DRM fractions isolated using Triton X-100 are considerably heavier than those isolated from homogenates treated with Brij96. The major polar lipid composition of DRMs derived from Brij96 treated homogenates have a higher proportion of aminophospholipids compared with choline phospholipids than Triton X-100 derived DRMs; this may indicate that DRMs from Brij96 treated homogenates are more closely related to the parent membrane in lipid composition. Solubilization by Triton X-100 at higher temperatures resulted in the appearance of a second detergent-resistant membrane fraction distinctly lighter in density than the membrane recovered at density 1.07 g/ml. Analysis of phospholipid composition of the brain homogenate during detergent treatment for up to 30 min at 37 °C showed a decreasing proportion of sphingomyelin. Treatment of homogenates at 37 °C appears to activate phospholipases/sphingomyelinases that may alter the lipid content of isolated DRMs. The presence of K +/Mg 2+ with Brij96 treatment results in DRM fractions with significantly thicker bilayers and of larger vesicle diameter than DRMs isolated from either Triton X-100 or Brij96 treated homogenates in the absence of cations.

Reclassification of Pseudomonas beijerinckii Hof 1935 as Chromohalobacter beijerinckii comb. nov., and emended description of the species

Pseudomonas beijerinckii (type strain DSM 7218(T)=ATCC 19372(T)=NCIMB 9041(T)) was isolated from salted beans and was first described by Hof in 1935. 16S rRNA gene sequence comparisons demonstrated its close relatedness (>97-99 %) to species of the genus Chromohalobacter. A recent isolate from salted herrings originating from the Baltic Sea, strain 3b, also clustered phylogenetically within this genus. Phenotypic features, substrate utilization, fatty acid profile, quinone and polar lipid composition and whole-cell protein patterns supported the similarity of strain 3b to P. beijerinckii DSM 7218(T) and confirmed its relatedness to members of the genus Chromohalobacter. The G+C content of the DNA from strain 3b and P. beijerinckii DSM 7218(T) was 60.4 and 60.7 mol%, respectively. DNA-DNA hybridization data showed that the two strains represent the same species, but are separated from Chromohalobacter canadensis, the closest species from a phylogenetic point of view. Therefore, the reclassification of Pseudomonas beijerinckii as Chromohalobacter beijerinckii comb. nov. (type strain DSM 7218(T)=ATCC 19372(T)=NCIMB 9041(T)) is proposed. The species description has been emended considering the new data on both the type strain and strain 3b.

Halorubrum lipolyticum sp. nov. and Halorubrum aidingense sp. nov., isolated from two salt lakes in Xin-Jiang, China

Two extremely halophilic archaea, strains 9-3(T) and 31-hong(T), were isolated from Aibi salt lake and Aiding salt lake in Xin-Jiang, China. Their morphology, physiology, biochemical features, polar lipid compositions and 16S rRNA gene sequences were characterized in order to elucidate their taxonomic status. The results from this study indicated that strains 9-3(T) and 31-hong(T) are members of the genus Halorubrum. Their physiological properties and polar lipid compositions are clearly different from those of the currently described species of Halorubrum. DNA-DNA relatedness values for strain 9-3(T) with respect to its closely related neighbours Halorubrum saccharovorum JCM 8865(T) and Halorubrum lacusprofundi JCM 8891(T) were 51.6 and 25.1 %, respectively, DNA-DNA relatedness values for strain 31-hong(T) with respect to its closely related neighbours Hrr. saccharovorum JCM 8865(T) and Hrr. lacusprofundi JCM 8891(T) were 29.4 and 44.9 %, respectively, and DNA-DNA relatedness between strains 9-3(T) and 31-hong(T) was 54 %. Thus, two novel species of the genus Halorubrum are proposed, Halorubrum lipolyticum sp. nov. (type strain 9-3(T)=CGMCC 1.5332(T)=JCM 13559(T)) and Halorubrum aidingense sp. nov. (type strain 31-hong(T)=CGMCC 1.2670(T)=JCM 13560(T)).

Comparison Between Two Different Levels of Replacement of Free-range Rearing by an Oleic Acid and-tocopherol Enriched Diet on the Quality of Fresh Meat from Iberian Duroc (50%) Pigs

The aim of this work was to study the effect of two types of pig feeding systems (known as recebo) on fatty acid composition, tocopherols contents and susceptibility to lipid oxidation in muscle. A total of 26 Iberian Duroc (50%) barrows were divided into two groups (named as short replacement (SR) and long replacement (LR) groups) according to length of replacement of free-range rearing (based on acorn and pasture) by an oleic acid and B-tocopherol (200 mg/kg) enriched concentrate feed (SR group: 67 days in free-range rearing and finished during 20 days with concentrate diet; LR: 55 days in free-range rearing, finished 50 days with concentrate). No differences were found in chemical composition and colour of Gluteo biceps muscle between the two management systems, except for B-tocopherol content, which showed higher content (p 0.001) in LR pigs than in SR pigs. The fatty acid composition of subcutaneous fat was slightly affected by feeding system. Total intramuscular and neutral lipids from Gluteo biceps muscle presented a higher proportion of C18: 1 n 9 (p 0.05) in SR than in LR pigs; however, no differences were found in total saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA). Composition of polar lipids revealed a higher proportion of MUFA and lower of total n 3 fatty acids in LR than in SR pigs. Feeding regime significantly affected susceptibility of muscle to iron-ascorbate-induced peroxidation. Muscles from pigs reared on SR system showing higher levels (p 0.05) of MDA after 50 and 100 min of incubation. These results indicate that the content of oleic acid and tocopherol in muscle depends on the levels of both provided by dietary means, more than the practised handling.

Effect of light intensity on the fatty acid composition of dinoflagellates symbiotic with hermatypic corals

We examined the effects of varying light intensity on fatty acid composition in symbiotic dinoflagellates (SD) isolated from hermatypic corals Millepora intricata , Pocillopora damicornis , Seriatopora caliendrum , Seriatopora hystrix and Stylophora pistillata . The corals were subjected to 95%, 30%, 8% and 2% of incident photosynthetic active radiation (PAR). Irradiance had a significant effect on fatty acid composition of polar lipids and triacylglycerols. SD showed substantial changes in the proportion of 16:0 as a response to variation in PAR. During adaptation to high light, the percentage of 16:0 increased in polar lipids and triacylglycerols. Additionally, the percentage of 14:0, 16:1(n-7) increased in triacylglycerols. Thus, high light conditions lead to an increase in storage products. Polar lipids of SD adapted to low levels of PAR had greater concentrations of 18:4(n-3), 20:5(n-3), 18:5(n-3) and 22:5(n-6) which are commonly involved in the formation of thylakoid membranes. Conversely, the amounts of 20:4(n-6) and 22:6(n-3) increased with increasing irradiance, suggesting an association with photosynthesis. The elevation in percentages of 18:4(n-3), 20:5(n-3) and 18:5(n-3) during exposure to low light was accompanied by an increase in chlorophyll a content in the SD cells. Light-dependent changes in fatty acid composition are probably due to the correlation of activity of photosystems with processes of production and desaturation of fatty acids.

Thalassobacter stenotrophicus Macián et al. 2005 is a later synonym of Jannaschia cystaugens Adachi et al. 2004, with emended description of the genus Thalassobacter

The type strains of Jannaschia cystaugens (LMG 22015(T)) and Thalassobacter stenotrophicus (CECT 5294(T)) were analysed by means of genomic DNA-DNA hybridization, comparison of 16S rRNA gene sequences and phenotypic properties determined under the same methodological conditions. J. cystaugens LMG 22015(T) showed DNA-DNA relatedness levels of 72% when hybridized with the genomic DNA of T. stenotrophicus CECT 5294(T). Sequence comparisons revealed that the 16S rRNA genes of the two strains had a similarity of 99.8%. The cellular fatty acid and polar lipid compositions of the two strains and their DNA mol% G+C contents were almost identical. Bacteriochlorophyll a (Bchl a) and polyhydroxybutyrate were produced by both strains under the same culture conditions. Their closest phylogenetic neighbours were Jannaschia helgolandensis and Jannaschia rubra; however, the low sequence similarity values (95.7-95.9%) and several important differences in phenotypic traits (ionic requirements, Bchl a production and polar lipids) support the distinction between the genera Thalassobacter and Jannaschia. Thus, we propose the unification of J. cystaugens (LMG 22015(T)) and T. stenotrophicus (CECT 5294(T)) as Thalassobacter stenotrophicus (type strain, CECT 5294(T)=DSM 16310(T)). An emended description of the genus Thalassobacter is also presented.

Influence of nitrogen deficiency on biochemical composition of the green alga Botryococcus

A study has been carried out to investigate the influence of nitrogen deficiency on intracellular lipid composition, including total fatty acid composition of lipids, polar lipids, and triacylglycerols, of the alga Botryococcus braunii Kutz IPPAS H-252 in batch culture. Under nitrogen limitation, the alga accumulates lipids as triacylglycerols and the total fatty acid (FA) composition changes: trienoic acids decrease (from 52.8-57.2 to 19.5-24.7% of the total FAs) and the oleic acid increases (from 1.1-1.2 to 17.1-24.4%) as does the saturated acids (from 23.7-26 to 32.9-46.1%). A similar rearrangement in the FA spectrum occurs at later times in the control culture, but it is less pronounced. Under nitrogen limitation, considerable changes in the polar lipid FAs are registered at day 13: saturated acids increase (from 28.6-35.5 to 76.8%) and all polyenoic acids markedly decrease (from 56.9-64.1 to 6.8%). Changes in the triacylglycerol fatty acid spectrum are seen on day 7: the oleic acid increases (from 14.7 to 34.2%) and remains at a high level till the end of the culture. In the control, triacylglycerols with large contents of oleic acid are detected at day 13, the total lipids and triacylglycerols still remaining unchanged.

Effect of Nitrogen Limitation on the Growth and Lipid Composition of the Green Alga Botryococcus braunii Kutz IPPAS H-252

The effect of nitrogen limitation in a medium on the composition of intracellular lipids in the alga Botryococcus braunii Kutz IPPAS H-252 in the course of culture development was investigated. Under the conditions of nitrogen limitation, the alga under investigation accumulated lipids as triacylglycerols, and this process was accompanied by substantial changes in the total fatty acid (FA) composition, which were manifested in a decrease in trienoic acids (from 52.8–57.2 to 19.5–24.7% of total FAs) and an increase in the content of oleic (from 1.1–1.2 to 17.1–24.4%) and saturated (from 23.7–26.0 to 32.9–46.1%) acids. In the control culture, the directionality of FA redistribution was less marked, and these changes were noticed at the later stages of culture development. Under nitrogen limitation, marked changes in the FA composition of polar lipids occurred by the 13th day, and they were characterized by an increase in the content of saturated acids (up to 76.8%) and a dramatic decrease in the content of all polyenoic acids (up to 6.8%). The changes in the FA composition of triacylglycerols were noticed as early as by the 7th day; these changes consisted in an increase in the content of oleic acid, and its high content (28.4–38.4%) was maintained up to the end of culturing. In the control culture, triacylglycerols with a high content of oleic acid were found by the 13th day, although, by this time, the content of total lipids and triacylglycerols did not change.

Partial replacement of fish oil by soybean oil on lipid distribution and liver histology in European sea bass (Dicentrarchus labrax) and rainbow trout (Oncorhynchus mykiss) juveniles

Summary A 12-week feeding trial was conducted to evaluate the effects of fish oil replacement by soybean oil, on lipid distribution and liver histology of two commercially important finfish species: rainbow trout (Oncorhynchus mykiss) and European sea bass (Dicentrarchus labrax). Sea bass (16.2 ± 0.5 g; mean ± SD) and rainbow trout (52.1 ± 0.5 g) juveniles were fed one of three isonitrogenous (500 g kg−1 CP) and isoenergetic (19 kJ g−1) diets, containing 0% (control, diet A), 25% (diet B) and 50% (diet C) soybean oil. At the end of the experiment, lipid deposition was evaluated in muscle, liver and viscera. Cholesterol and triglycerides levels were also determined in plasma. Tissue total, neutral and polar lipid composition (g kg−1 total lipids) showed no significant differences within species, regardless the dietary treatment. The same trend was observed for plasma parameters (P > 0.05). Viscera were the preferential tissue of lipid deposition, with 252–276 and 469–513 g kg−1 total lipid content in trout and sea bass, respectively. Dietary fish oil replacement had no effect on either hepatic lipid droplets accumulation or degree and pattern of vacuolization in the observed liver sections. These data suggest that both sea bass and trout can be fed diets containing up to 50% soybean oil without adverse effects on tissue lipid composition or liver histology.

Organic solvent tolerance of halophilic archaea, Haloarcula strains: Effects of NaCl concentration on the tolerance and polar lipid composition

Strains of halophilic archaea, Haloarcula vallismortis and two Haloarcula strains OHF-1 and OHF-2, showed high tolerance to organic solvents at high media NaCl concentrations. For example, the lowest log Pow of the solvent which allowed growth (log Pow is the common logarithm of the partition coefficient of a given solvent in a mixture of n-octanol and water) for H. vallismortis was 5.1 at 20% NaCl and 4.4 at 30% NaCl. The solvent tolerance of Haloarcula argentinensis, on the other hand, was not affected by the NaCl concentration. Cells of strains OHF-1 and OHF-2 were of triangular or irregular morphology but became spherical in cultures in NaCl media overlaid with cyclohexane (log Pow=3.4), but returned to the triangular shape when the organic solvent evaporated from the medium. When cells of strains OHF-1, OHF-2, and H. argentinensis were grown in NaCl media in the presence of n-decane, they contained less phosphatidylglycerol and more phosphatidylglycerosulfate and phosphatidylglycerophosphate methyl ester than when grown without added n-decane. When the solvent was removed from the media after cultivation, the levels of these compounds returned to their initial ones.

Requirement of n-3 long chain polyunsaturated fatty acids for European sea bass ( Dicentrarchus labrax) juveniles: growth and fatty acid composition

European sea bass juveniles (14.4±0.1 g mean weight) were fed diets containing different levels of fish oil then of n-3 highly unsaturated fatty acids (n-3 HUFA) for 12 weeks. The fish performance as well as fatty acid (FA) composition of neutral and polar lipids from whole body after 7 and 12 weeks feeding were studied. The requirements of juvenile sea bass for n-3 highly unsaturated fatty acids (n-3 HUFA) were studied by feeding fish diets containing six different levels of n-3 HUFA ranging from 0.2% to 1.9% of the diet, with approximately the same DHA/EPA ratio (1.5:1). The growth rate at the end of the trial showed significant differences. Fish fed low dietary n-3 HUFA (0.2% DM of the diet) showed significantly lower growth than the diet 3 (0.7%), then no further improvement ( P>0.05) of growth performance was seen by elevating the n-3 HUFA level in the diet up to 1.9% (diet 6). No difference in feed efficiency, protein efficiency ratio or protein retention was observed among treatments, nor in protein and total lipid content. However, the n-3 HUFA levels in diets highly influenced fish fatty acid composition in neutral lipid, while polar lipid composition was less affected. Comparison of polar lipid content after 7 or 12 weeks indicated that DHA remained stable at the requirement level, while arachidonic acid decreased with time. Results of this experiment suggest that the requirement for growth of n-3 HUFA of juvenile sea bass of 14 g weight is at least 0.7% of the dry diet.

Lipolysis in dry-cured ham: Influence of salt content and processing conditions

Fatty acid composition of neutral lipids (NLs), polar lipids (PLs) and free fatty acids (FFA) from the intramuscular fat of Semimembranosus and Biceps femoris muscles was analysed in 46 Iberian dry-cured hams processed with different amounts of salt (6% high salt batch – HS vs. 3% low salt batch – LS w/w) and different processing systems (traditional – T vs. modified – M). Total amounts of saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids in NLs decreased in similar proportions during processing of the hams as well as SFA, MUFA and PUFA in the PL fraction, whereas the amounts of SFA, MUFA and PUFA of FFAs significantly increased in Semimembranosus and Biceps femoris muscles. The amount of total fatty acids (TFA), from NLs and PLs, decreased in both muscles throughout the processing. Such a decline was more intense in HS hams than in LS ones, which could be a sign of a promoting effect of sodium chloride on lipolysis. However, the increase in FFA content throughout processing was not more intense in HS hams. Processing conditions studied in this work did not affect the changes in the fatty acid content of each fraction.

Improvement of a solid phase extraction method for analysis of lipid fractions in muscle foods

The most used method for muscle lipid fractionation into major lipid classes was modified for improving its separation efficiency. Extracted lipids from a masseter muscle of one Iberian pig were separated into neutral lipids (NL), free fatty acids (FFA) and polar lipids (PL) using aminopropyl minicolumns, following the extensively used method of Kaluzny et al. [1] (old method-OM-) and a method based on that, developed by Pinkart et al. [2] with some (modifications modified method–MM). Obtained lipid classes were further analysed by TLC and lipid fractions were identified. TLC evidenced the presence of a certain amount of PL in the NL fraction obtained with the OM. On the other hand, using the MM only an almost undetectable presence of PL was evidenced in the NL fraction. Fatty acid composition of NL, PL and FFA obtained with each method was studied by gas chromatography. Fatty acid profile of NL was strongly influenced by the separation method used. Thus, NL obtained using the OM showed higher amounts of saturated fatty acids (SFA) and polyunsaturated fatty acids (PUFA) and lower of monounsaturated fatty acids (MUFA) than those obtained using the MM. Moreover, NL obtained using the OM showed the presence of fatty alcohols, constituents of phospholipids (PhL) absent or present only in trace amounts in acylglycerols. This profile reflects the coelution of PL in the NL fraction. Fatty acid profile of FFA and PL fractions was also influenced by the solid phase extraction (SPE) method used, but to a lesser extent.

Incorporation of ovalbumin into ISCOMs and related colloidal particles prepared by the lipid film hydration method

The aim of this study was to investigate the incorporation of a model antigen, fluorescently labelled ovalbumin (FITC-OVA), into various colloidal particles including immune stimulating complexes (ISCOMs), liposomes, ring and worm-like micelles, lamellae and lipidic/layered structures that are formed from various combinations of the triterpene saponin Quil A, cholesterol and phosphatidylethanolamine (PE) following hydration of PE/cholesterol lipid films with aqueous solutions of Quil A. Colloidal dispersions of these three components were also prepared by the dialysis method for comparison. FITC-OVA was conjugated with palmitic acid (P) and PE to produce P-FITC-OVA and PE-FITC-OVA, respectively. Both P-FITC-OVA and PE-FITC-OVA could be incorporated in all colloidal structures whereas FITC-OVA was incorporated only into liposomes. The incorporation of PE-FITC-OVA into all colloidal structures was significantly higher than P-FITC-OVA ( P<0.05). The degree of incorporation of protein was in the order: ring and worm-like micelles<liposomes and lipidic/layered structures<ISCOMs and lamellae. The incorporation of protein into the various particles prepared by the lipid film hydration method was similar to those for colloidal particles prepared by the dialysis method (provided both methods lead to the formation of the same colloidal structures). In the case of different colloidal structures arising due to the preparation method, differences in encapsulation efficiency were found ( P<0.05) for formulations with the same polar lipid composition. This study demonstrates that the various colloidal particles formed as a result of hydrating PE/cholesterol lipid films with different amounts of Quil A are capable of incorporating antigen, provided it is amphipathic. Some of these colloidal particles may be used as effective vaccine delivery systems.

Mitochondrial lipids in Bufo arenarum full-grown oocytes.

Both the content and composition of polar and neutral lipids from the mitochondrial fraction of ovarian full-grown Bufo arenarum oocytes were analysed in the present study. Triacylglycerols (TAG) represent 33% of the total lipids, followed by phosphatidylcholine (PC), free fatty acids (FFA) and phosphatidylethanolamine (PE). Diphosphatidylglycerol (DPG) or cardiolipin, a specific component of the inner mitochondrial membrane, represents about 4% of the total lipid content. Palmitic (16:0) and arachidonic (20:4n6) acids are the most abundant fatty acids in PC and PE, respectively. DPG is enriched in fatty acids with carbon chain lengths of 18, the principal component being linoleic acid. In phosphatidylinositol (PI), 20:4n6 and stearic acid (18:0) represent about 72 mol% of the total acyl group level. The main fatty acids in TAG are linoleic (18:2), oleic (18:1), and palmitic acids. The fatty acid composition of FFA and diacylglycerols (DAG) is similar, 16:0 being the most abundant acyl group. PE is the most unsaturated lipid and sphingomyelin (SM) has the lowest unsaturation index.

Effect of Choline Chloride on the Lipid Content and Composition in the Leaves of Principal Magnetically-Oriented Radish Types

The effects of radish seed treatment with choline chloride on the number and weight of leaves, the weight of roots, as well as the content and composition of polar and neutral lipids and their component fatty acids in the leaves of principal magnetically-oriented types (MOTs) of radish (cv. Rosovo-krasnyi s belym konchikom), that is, North–South (NS) and West–East (WE) ones, were investigated. It was shown that seed treatment with 1% choline chloride increased the proportion of WE MOT in plant population. In spring and in autumn, this treatment increased the weight of roots of the NS MOT plants, but did not affect this index in the WE MOT plants. In the spring NS MOT plants, choline chloride treatment did not change the absolute content of polar lipids as compared to the control, but in autumn, this index increased. Meanwhile, in the WE MOT plants, it increased in spring and did not change in autumn. In the spring NS MOT plants, the content of neutral lipids increased, but in the autumn plants, it did not change. At the same time, in the WE MOT plants, this index decreased both in spring and in autumn. Seed treatment with choline chloride resulted in a substantial increase in the total content of phospholipids, in particular, that of phosphatidylcholine and phosphatidylethanolamine, in the NS and WE MOT plants sampled both in spring and in autumn. In addition, the ratio of unsaturated to saturated fatty acids, as well as that of linolenic to linoleic fatty acids, somewhat increased in the NS MOT leaf lipids, but decreased in the WE MOT ones. Presowing treatment of radish seeds with choline chloride variously and sometimes oppositely affected the content and composition in the NS and WE MOT leaf lipids. This seems to be caused by different response of these MOTs to the environmental factors.