Structural Characteristics and Fatty Acid Composition of Psophocarpus tetragonolobus Seeds

Winged bean (Psophocarpus tetragonolbtis) seed coat in the hilarregion consists of a double layer of sclereids, tracheid barand spongy parenchyma cells. This is contrasted to the seedcoat structure on either side of the hilar region, which hasa single layer of sclereids, columnar cells and crushed parenchymacells. Cotyledonary cells are large (50 to 100µm in diameter)and have cell walls 2·4 to 4·7 µm thickwith pit-pair structures. Protein bodies and lipid bodies arethe main structural components of the cytoplasm while only asmall number of starch granules are present in each cell. Themajor portion of the lipid can be removed by non-polar solventsand contains oleic and linoleic acids as the predominant unsaturatedfatty acids. High levels of behenic acid were present in both‘free’ and ‘bound’ lipids. Psophocarpus tetragonolobus (L.) DC., winged bean, seed structure, seed coat, protein bodies, lipid bodies, fatty acids, oleic acid, linoleic acid     

Unsaturated Fatty Acid Synthesis During the Development of Isolated Sunflower (Helianthus annuus L.) Seeds

The effect of temperature on unsaturated fatty acid synthesisin developing sunflower seed embryos (Helianthus annuus L.)has been studied using isolated seeds grown in culture. Variabilitybetween individual embryos in the response to temperature wasalso investigated. Oil and dry matter accumulation in cultured embryos were similarto those of embryos allowed to develop in intact plants, andthe effect of increasing temperature in lowering the amountof linoleic acid in seed oil was reproduced in cultured embryos.The isolated seed culture system, therefore, constitutes a suitablemodel system for studies of oil synthesis in developing sunflowerembryos. The decrease in linoleic acid synthesis in response to highertemperature was detectable after only 18 day-degrees incubation,and the incorporation of labelled substrates suggests that alterationsin the fatty acid composition of seed oil in response to temperatureare produced by an effect on the desaturation of newly synthesizedoleate rather than through turnover of existing lipid. Variation in fatty acid composition between individual embryosgrown at constant temperature was considerable. The detectionof embryos with high linoleic acid levels following growth athigh temperature indicates that potential may exist for theselection of cultivars for temperature-stable fatty acid compositionin sunflower oil. Key words: Fatty acid synthesis, Helianthus annuus, Sunflower seeds     

Characteristics of Sugar, Amino Acid and Phosphate Release from the Seed Coat of Developing Seeds of Vicia faba and Pisum sativum

After removal of the embryo from developing seeds of Vicia fabaL. and Pisum sativum L., the ‘empty’ ovules werefilled with a standard solution (pH 5.5). Seed coat exudatesof both species were collected during relatively long experiments(up to about 12 h) and the concentration of sugar (mainly sucrose),amino acids and phosphate in the exudate measured. A discussionis presented on the amino acid/sugar ratio and the phosphate/sugarratio in the seed coat exudate. A pretreatment (15 min) withp-chloromercuribenzenesulphonic acid (PCMBS) reduced the releaseof sugar, amino acids and phosphate from broad bean seed coats.After excision of ‘empty’ ovules of Vicia faba andPisum sativum from the maternal plant, 2–4 h after thistreatment a strong difference became visible between sucroserelease from excised seed coats and sucrose release from attachedseed coats. Similarly, when the rate of phloem transport ofsucrose into an ‘empty’ ovule of Vicia faba or Pisumsativum was reduced by a sub-optimal mannitol concentrationin the solution, a reduced rate of sugar release from the seedcoat could be observed. Excision and treatment with a sub-optimalmannitol concentration reduced the release of amino acids toa lesser extent than for sucrose. These treatments did not reducethe rate of phosphate release from the seed coat. Key words: Seed development, Seed coat exudate, Phloem transport     

Changes in Lipids of Bean Seeds (Phaseolus vulgaris) and Corn Caryopses (Zea mays) Aged in Contrasting Environments

Seeds of French bean (Phaseolus vulgaris L. cv. The Prince)and caryopses of sweet corn (maize; Zea mays L.F1 hybrid Firstof All) were stored in environments of 79% relative humidityand 25 °C, 80% r.h. and 40 °C or 100% r.h. and 45 °C,giving ageing (loss of gcrminability and vigour) over periodsof months, weeks or days, respectively. The relationship betweenchanges in lipids and changes in germinability or vigour wasunaffected in general by the speed of ageing. In the corn caryopsesthere was no evidence of hydrolysis of phospholipids or peroxidationof fatty acids during ageing. In the bean seeds phosphatidicacid increased during the ageing period and phosphatyl cholinedeclined. The percentage of fatty acids as hnolenic acid initiallyfell during bean ageing, but in the slower ageing conditionsit rose again as germination reached zero. In bean, the presenceof phosphatidic acid could be a sensitive indictator of lossof vigour, but relative proportions of the different fatty acidswould be a misleading indicator of quality. Rapid artificialageing may be an adequate model, in some species, of ageingat moderate speeds and of ageing under some ambient conditions. French bean (Phaseolus vulgaris L. cv. The Prince), sweet corn (maize, Zea mays L., Fl hybrid First of All), seed ageing, phospholipids, fatty acids     

Repair of membrane hyperpermeability in L. plantarum during partial reversal of lipid deficiency

Previous studies suggest that the reduced amino acid accumulation capacity of pantothenate-deficient $\text{L. plantarum}$ is caused by a lipid deficiency which results in membrane hyperpermeability. The accumulation defect can be reversed by supplying such cells with saturated or unsaturated fatty acids which are incorporated into the major lipid constituents. Simultaneous measurement of ³H-amino acid uptake and ¹⁴C-fatty acid incorporation revealed that some unsaturated fatty acids promote an 80% reversal of the amino acid accumulation deficit when the cells have taken up only enough fatty acid to replace 12 to 20% of the lipid deficit. Apparently, only a small fraction of the absent lipid plays a decisive role in membrane permeability.     

Differential Effects of the Substituted Pyridazinone Herbicide Sandoz 9785 on Lipid Composition and Biosynthesis in Photosynthetic and Non-Photosynthetic Marine Microalgae: II. FATTY ACID COMPOSITION

The effect of the substituted pyridazinone, 4-chloro-5-(dimethylamino)-2-phenyl-3(2H)-pyridazinone(Sandoz 9785), on fatty acid synthesis in two photosyntheticspecies (Chroomonas salina and Nannochloropsis oculata) andone non-photosynthetic species (Crypthecodiniun cohnii) of marinemicroalgae were examined. Effects were more obvious in C. salinathan in C. cohnii or N. oculata. In C. cohnii the relative distributionamongst polyunsaturated fatty acids (PUFA) of radioactivityincorporated from ¹⁴C-acetate was not influenced by the herbicideto any great extent and no major changes in the fatty acid compositionof lipid fractions were observed. In C. salina, Sandoz 9785reduced the proportions of radioactivity recovered in 20: 5(n–3) and 22: 6 (n–3) of the phospholipid fraction.The distribution pattern of radioactivity in the fatty acidsof monogalactosyldiacylglycerol (MGDG) in this species was notgreatly affected by the herbicide whereas its presence significantlyreduced the proportions recovered in 18: 4 and 20: 1 in digalactosyldiacylglycerol(DGDG). The level of 20: 5 (n–3) in DGDG of C. salinawas increased from 4.0 to 19.8% by growing the algae in thepresence of Sandoz 9785. The only notable effect of the herbicideon the synthesis of PUFA in N. oculata was a reduction from18.3% to 11.3% of the proportion of radioactivity recoveredin 20: 5 in phospholipids. The herbicide had no effect on thedistribution of radioactivity in PUFA of galactolipids or onthe fatty acid composition of lipid fractions. The results arediscussed in relation to the potential role of galactolipidsand phospholipids as substrates for desaturations involved inthe formation of long chain PUFA in marine microalgae. Key words: Microalgae, herbicide, fatty acids     

Effectiveness of the fatty acid and sterol composition of seeds for the chemotaxonomy of Coffea subgenus Coffea

The chemotaxonomic relationships between Coffea (subgenus Coffea) species have been poorly studied to date and the compounds tested so far - chlorogenic acids, diterpenoids and purine alkaloids - did not enable the establishment of phylogenetic relationships analogous to those revealed by chloroplast and nuclear DNA studies. In the present study, the relationships between African Coffea species were assessed on the basis of their seed lipid composition. Fatty acids and sterols were determined in 59 genotypes belonging to 17 distinct Coffea species/origins. Principal Component Analysis of fatty acid and sterol data enabled easy identification of the few species for which one or several compounds could serve as a quantitative signature. Hierarchical Clustering classified the Coffea species in seven groups with both fatty acids and sterols. However, while groupings based on seed fatty acid composition showed remarkable ecological and geographical coherence, no phylogeographic explanation was found for the clusters retrieved from sterol data. When compared with previous phylogenetic studies, the groups deduced from seed fatty acid composition were remarkably congruent with the clades inferred from nuclear and plastid DNA sequences.     

Orthodox Behaviour of Oil Palm Seed and Cryopreservation of the Excised Embryo for Genetic Conservation

Desiccation experiments have shown the oil palm seed to be orthodox,not recalcitrant, in character. There is a significant differencein water content between the whole seed and the embryo whichis maintained despite desiccation, and results in the failureof sub-zero storage of whole seeds. The successful recoveryof viable, excised embryos from liquid nitrogen, and their subsequentregrowth in vitro, suggests a practical technique for the longterm conservation of the genetic resources of the species. Elaesis guinensis L, oil palm embryo, cryopreservation, recalcitrant seed     

Generation and esterification of electrophilic fatty acid nitroalkenes in triacylglycerides

Electrophilic fatty acid nitroalkenes (NO₂-FA) are products of nitric oxide and nitrite-mediated unsaturated fatty acid nitration. These electrophilic products induce pleiotropic signaling actions that modulate metabolic and inflammatory responses in cell and animal models. The metabolism of NO₂-FA includes reduction of the vinyl nitro moiety by prostaglandin reductase-1, mitochondrial β-oxidation, and Michael addition with low molecular weight nucleophilic amino acids. Complex lipid reactions of fatty acid nitroalkenes are not well defined. Herein we report the detection and characterization of NO₂-FA-containing triacylglycerides (NO₂-FA-TAG) via mass spectrometry-based methods. In this regard, unsaturated fatty acids of dietary triacylglycerides are targets for nitration reactions during gastric acidification, where NO₂-FA-TAG can be detected in rat plasma after oral administration of nitro-oleic acid (NO₂-OA). Furthermore, the characterization and profiling of these species, including the generation of beta oxidation and dehydrogenation products, could be detected in NO₂-OA-supplemented adipocytes. These data revealed that NO₂-FA-TAG, formed by either the direct nitration of esterified unsaturated fatty acids or the incorporation of nitrated free fatty acids into triacylglycerides, contribute to the systemic distribution of these reactive electrophilic mediators and may serve as a depot for subsequent mobilization by lipases to in turn impact adipocyte homeostasis and tissue signaling events.     

Lipids in Acanthodiaptomus denticomis during starvation and fed on three different algae

Variations in the levels of triglycerides, wax esters and polarlipids were determined in adults of the calanoid copepod Acanthodiaptomusdenticornis when freshly caught, starved or fed on the followingalgae: Anabaena spiroides, Cyclotella pseudostelligera and Pediastrumduplex. Over 7 days starvation, triglycerides and wax esterswere almost entirely used up by the copepods. Subsequent feedingover 20 days partially restored triglycerides but restored onlya relatively small fraction (<20%) of wax esters in the animals.Differences in the lipid restoration were found: the restoredtriglyceride level was higher in animals feeding on Cyclotellapseudostelligera or Pediastrum duplex than in those feedingon Anabaena spiroides. Fatty acid composition of neutral lipidswas closely linked to fatty acid composition of algae. The resultssuggest that lipid and fatty acid contents of Acanthodiaptomusdenticornis are good indices of the copepod's nutritional statusand short-term (0–20 days) feeding history.     

Energetics of Plant Growth Under Anoxia: Metabolic Adaptations of Oryza sativa and Echinochloa phyllopogon

Unlike most plant species, Oryza sativa L. cv. S-201 and Echinochloaphyllopogon (Stev.) Koss germinate and grow under anaerobicconditions. In both species, the radicle or shoot emerged byday 3 when the seeds were germinated in air or N₂. Under eithercondition, shoot and/or root dry weight (d. wt) increased linearlyfrom day 3 to day 7, with a corresponding decrease in seed d.wt. In anaerobically grown O. sativa, d. wt accumulation wasreduced to 7% of that in air whereas d. wt lost from the seedwas reduced to only 37%. No root growth occurred during anaerobicgermination and shoot d. wt accumulation accounted for 10% ofthe d. wt lost from the seed. In E. phyllopogon, d. wt accumulationduring anoxia was 25% of that in air, but loss of d. wt fromthe seed was 44% of the aerobic rate. In air, 48% of the d.wt lost from the seed was converted to shoot or root d. wt.Like O. sativa, E. phyllopogon does not produce a root underN₂, but shoot growth accounted for 27% of the d. wt lost fromthe seed. Thus, either in air or N₂, E. phyllopogon was moreefficient at converting seed reserves to shoot/root structuraldry matter than O. sativa . Based on changes in metabolite pools,O. sativa appeared to shift exclusively to fermentation duringanaerobic growth. In E. phyllopogon, however, fermentation alonecannot satisfy the energy requirement for growth without O₂.Rather, fermentation, coupled with limited tricarboxylic acid(TCA) cycle operation could supply sufficient ATP for growthunder anaerobic conditions. An active oxidative pentose phosphatepathway and lipid synthesis were discussed as important mechanismsfor converting NADH to NAD, a necessary cofactor for fermentationand TCA cycle activity.Copyright 1994, 1999 Academic Press Anaerobiosis, Echinochloa phyllopogon, energetics model, fermentation, mitochondrial activity, Oryza sativa, rice, tricarboxylic acid cycle, watergrass     

Interaction Between Cryopreservation, Rewarming Rate and Seed Humidification on the Germination of Two Spanish Endemic Species

The effects of humidification, storage in liquid nitrogen (1or 30 d) and rewarming rate on seed germination were studiedin two Spanish endemics. Humidification resulted in higher germinationpercentages only in the species with hard covers, especiallyin slowly rewarmed seeds. In an experiment lasting 21 weeks,seeds stored in liquid nitrogen were removed for 10 min eachweek to mimic the withdrawal of samples from a seed bank; thishad no effect on germination.Copyright 1998 Annals of BotanyCompany Centaurea hyssopifolia,Limonium dichotomum, cryopreservation, cypsela, endemics, germination, humidification, seeds.     

Maize seedlings produced from dry seeds exposed to liquid nitrogen display altered levels of shikimate pathway compounds

In light of climate change and risks of food insecurity, it is becoming increasingly important to preserve plant germplasm in genebanks. Storage of seeds, particularly via cryopreservation, is one of the most proficient methods for ex situ plant germplasm conservation. Whilst seed cryo-banking can have little, to no, or even beneficial effects on subsequent seedling vigor in some species, it can lead to a number of plant abnormalities (morphological and physiological). This study investigated the effects of maize seed cryopreservation on seedling growth (until 14 d) and levels of selected amino acids produced in the shikimate pathway, a major link between primary and secondary metabolism. Seed cryopreservation reduced FW in recovered seedlings, reduced caffeic acid (2.5-fold decrease), and increased levels of all other shikimate pathway–related compounds assessed: phenylalanine (2.9-fold increase), tyrosine (2.6-fold increase), and shikimic (2.1-fold increase) and protocathecuic (3.1-fold increase) acids in cotyledons. Our results suggest that maize seed cryopreservation results in seedlings that exhibit signs of an ‘overly’ efficient and caffeic acid–deficient shikimate pathway, possibly related to their reduced growth during a highly vulnerable growth stage. However, these metabolic abnormalities manifested most severely in the maternal (cotyledonary), as opposed to vegetative (roots, stems, and leaves), tissues and hence are likely to disappear when the seedlings shed the cotyledons and become completely autotrophic.

     

Distribution of Diacylglycerylhydroxymethyltrimethyl-{beta}-alanine (DGTA) and Phosphatidylcholine in Brown Algae

Lipids were analyzed in thirteen species of brown algae collectedat the seashore near Tokyo, Japan. Diacylglycerylhydroxymethyltrimethyl-ß-alanine(DGTA), a recently identified betaine lipid, was found as amajor lipid component in eight species of brown algae examined,namely, Ishige okamurai, Dictyota dichotoma, Pachydictyon coriaceum,Padina arborescens, Hizikia fusiformis, Sargassum horneri, S.ringgoldianum and S. thunbergii. However, phosphatidylcholine(PC) was not detected in any of these algae except I. okamurai.By contrast, PC was found as a major lipid component in fiveother species, namely, Colpomenia sinuosa, Endarachne binghamiae,Scytosiphon lomentarius, Eisenia bicyclis, Undaria pinnatifida.These algae in turn did not contain detectable amounts of DGTA.The fatty acid composition of four selected species, S. lomentarius,U. pinnatifida, D. dichotoma and H. fusiformis, was also studied.The fatty acid components of DGTA in D. dichotoma and H. fusiformiswere similar to those of PC in U. pinnatifida, the major componentsbeing 16:0, 18:2 and 20:46 (also 16:1 in D. dichotoma). (Received December 14, 1990; Accepted April 10, 1991)     

Origin of Amino Acids in Datura stramonium Seeds

¹⁴C isotope studies show that the seeds of Datura stramoniumL. can produce a number of amino acids (particularly alanine,glutamate, phenylalanine, and tyrosine) from a supply of sucroseand nitrate. These amino acids can be incorporated into theseed protein. The bulk of the amino acids incorporated into the seed proteinmust, however, be supplied by adult leaves in the proximityof the fruit, either as the amino acids themselves, or theirimmediate precursors. The major free-amino-acid products of Datura leaves are theamides asparagine and glutamine.     

中国萤火虫云南窗萤荧光素酶cDNA的克隆表达和序列分析(英文）

从一种来自中国日行性萤火虫（云南窗萤）发光器官mRNA中克隆、测序并表达了有功能的荧光素酶。云南窗萤荧光素酶的cDNA序列有1 647个碱基,编码548个氨基酸残基。从推测得到的氨基酸序列的比对分析得出：云南窗萤的荧光素酶与来自Lampyris noctiluca, L. turkestanicus和Nyctophila cf. caucasica三种萤火虫的荧光素酶有97.8%的序列一致性。从推测得出的氨基酸序列进行系统发育分析,其结果表明：云南窗萤和Lampyris+Nyctophila聚在一起, 与同属的发光强夜行性的萤火虫不形成的单系。云南窗萤荧光素酶在大肠杆菌中表达的条带大约70 kDa,并且在有荧光素存在时发出黄绿色荧光。对荧光素酶的结构模拟和分析表明,云南窗萤荧光素酶基因的氨基端和羧基端结构域之间的裂沟处存在这5个多肽环,这正是从其他荧光素酶推测得到的催化荧光反应时的底物结合位点。云南窗萤和窗萤属的其他3种萤火虫的荧光素酶相比,有13个不同氨基酸位点,位于模拟分子结构的表面。对于这些多肽环、不同氨基酸残基和晶体结构的进一步研究有利于解释日行和夜行性萤火虫荧光素酶的差异。     

Lipid and Fatty-acid Composition of Diatoms

The lipids and fatty acids of two freshwater diatoms Nitzschiapalea Kutz, Navicula muralis Lewin, and one marine species,Navicula incerta Grun. have been studied. The major lipid components in all species were triglycerides,monogalactosyl, digalactosyl and sulphoquinovosyl diglycerides,phosphatidyl glycerol, phosphatidyl choline (lecithin), andphosphatidyl ethanolamine; while palmitoleic, palmitic, eicosapentaenoicand eicosate-traenoic acids were the major fatty acid constituents.The two galactolipids, monogalactosyl and digalactosyl diglyceridescontained large amounts of C₁₆ and C₂₀ polyunsaturated fattyacids. Lipids of diatoms, whether grown in the light or in the dark,were the same apart from quantitative differences. More storagelipids such as triglycerides were synthesized in the light thanin the dark.     

Effect of Potassium on Sucrose and Amino Acid Release from the Seed Coat of Developing Seeds of Pisum sativum

After removal of the embryo from developing seeds of Pisum sativum,the ‘empty’ ovules (seed coats without enclosedembryo) were filled with a solution (pH 5.5) containing mannitol(usually 400 mM) to which various salts were added. A solutioncontaining two isotopes ((a) [²H]-sucrose/[–¹⁴C]aminoisobutyricacid (AIB) or (b) [³H]valine/[₁₄C]asparagine mixture) was administeredto the plant via the petiole subtending the fruiting node, and[²H]solute and [¹⁴C]solute unloading from the seed coat wasmeasured, in pulse-labelling experiments of about 5 h. The presenceof 25 or 50 mM K⁺ in the ‘empty’ ovule enhancedthe release of sucrose from the seed coat particularly duringthe first hours of the experiment, but the stimulating effectof K⁺ on the release of labelled solutes derived from aminoacids was much smaller. The presence of 25 mM CaCl₂ did notaffect the release of sucrose or amino acids from the seed coat.The effect of K⁺ on sucrose and amino acid release is explainedas an inhibition of sucrose and amino acid resorption from theseed coat apoplast into seed coat cells, after unloading fromthe seed coat unloading sites. It is suggested that amino acidrelease is much less affected by K⁺ than sucrose release, becausefar less resorption of amino acids by seed coat parenchyma cellstakes place during amino acid transport into the seed coat cavity. Pisum sativum, pea, assimilate transport, assimilate unloading, seed-coat exudate, seed development, sucrose resorption, surgical treatment     

Change in sugar, sterol and fatty acid composition in banana meristems caused by sucrose-induced acclimation and its effects on cryopreservation

To understand the mechanisms of sucrose‐induced acclimation in relation to plant cryopreservation, sugars, sterols, fatty acids of different lipid fractions (neutral lipids, glycolipids and sphingolipids and phospholipids), as well as free fatty acids were analyzed in proliferating meristem cultures of different banana varieties. The four banana varieties that were selected show different post‐thaw shoot regeneration rates (0–53.4%). All mentioned parameters were analyzed using (1) control meristems that were cultured on a normal sucrose concentration (0.09 M), which resulted in low survival after cryopreservation; and (2) 2‐week sucrose precultured meristems (0.4 M). This sucrose preculture, essential for regeneration after cryopreservation, resulted in a significant increase of each of seven sugars detected. The ratio of stigmasterol/sitosterol (St/Si) in sucrose‐pretreated meristems significantly increased. The sucrose pretreatment also resulted in a significant increase of total fatty acid content of the neutral lipid fraction and of the glycolipid and sphingolipid fraction, as well as the total free fatty acid content. The individual fatty acid content of the phospholipids was differently changed by the sucrose pretreatment for the given varieties studied. In most cases, sucrose pretreatment resulted in an increase of the double bond index (DBI) in the neutral lipids and a decrease of DBI in the glycolipids and sphingolipids, in phospholipids as well as in free fatty acids. Principal component analysis of all collected data revealed that (1) for the control material, sucrose and total sugar contents were closely linked to the post‐thaw shoot regeneration, suggesting that sucrose and total sugar may be main limiting factors to survive cryopreservation; (2) accumulation of large quantities of sugars (glucose, fructose, sucrose and total sugar) in sucrose‐pretreated material cannot explain the differences in survival after cryopreservation of the four banana varieties. We assume that a minimal amount of sugars is needed in meristem cultures to survive cryopreservation. Still, other limiting factors do influence the survival following the sucrose pretreatment. We observed that the parameters which are closely linked to the post‐thaw shoot regeneration are a minimal change in the ratios of St/Si, the minimal change of the DBI of phospholipids and free fatty acids, as well as linoleic acid content (C18:2); and (3) inositol, raffinose, myristic acid (C14:0) and oleic acid (C18:1) were present in small quantities; however, they could be correlated to survival after cryopreservation, suggesting that they may be also involved in cryopreservation process.