Lipids in developing and mature rice grain

The neutral fraction of nonstarch lipids in developing brown rice (Oryza sativa L., cv IR42) was accumulated up to 16 days after flowering (DAF), but phospholipids and glycolipids increased only up to 8 DAF. Fatty acids accumulated in nonstarch lipids until 12 DAF. However, the proportion of linolenic acid in the lipid fraction decreased and that of oleic acid increased during this period. Accumulation of fat-by-hydrolysis in the brown rice occurred until 20 DAF and followed closely that of starch. The proportion of linolenic acid decreased and that of linoleic acid increased until 16 DAF. The fatty acid composition of fat-by-hydrolysis and starch lipids were identical and fat-by-hydrolysis accounted for 48% by weight of starch lipids. Nonstarch lipids were mainly composed of triglycerides and were located in the bran and embryo of mature brown rice. Starch lipids were mainly composed of lysophosphatidyl choline, free fatty acids and lysophosphatidyl ethanolamine, and were located in the endosperm.     

稻米直链淀粉含量的形成及其与灌浆结实期温度的关系

通过多类型品种的田间分期番种和人工气候箱控温处理等试验,对稻米直链淀粉含量（Ａｍｙｌｏｓｅ ｃｏｎｔｅｎｔ,简称ＡＣ）的形成动态变化特征及灌浆结实期温度的影响效应进行了分析。结果表明：水稻灌浆结实过程中稻米ＡＣ的形成动态变化过程叮嘱一次或二次曲线进行模拟,灌浆初期籽粒中的ＡＣ值很低,随之急剧上升,至２０～３０ｄ左右达到最大值,然后ＡＣ的变化基本趋于稳定;稻米ＡＣ的形成变化与籽粒于物质积累过程喑存在     

Effect of cadmium on fatty acid composition of lipids in the shoots of Karelian birch cultured in vitro

The effects of cadmium (10^?6, 10^?5, 10^?4, and 10^?3 M) on the growth and development of stem apical meristem and fatty acid (FA) composition of particular lipid fractions (neutral lipids, glyco-, and phospholipids) were investigated in the shoots of Karelian birch (Betula pendula var. carelica (Mercklin) Hämet-Ahti) produced in vitro. Low cadmium concentration (10^?6 M) slightly stimulated shoot morphogenesis. However, at the concentration of 10^?4 M, shoot growth and development was terminated, and the concentration of 10^?3 M turned out to be critical (the meristem died within the first 5 days). The presence of Cd in the medium considerably affected FA composition in the shoots. The most pronounced changes occurred in the fraction of glycolipids, and the extent of adverse influence significantly depended on metal concentration in the medium. At the Cd concentration of 10^?4 M, the content of di-and trienoic FAs decreased by 3–4 times, whereas the level of monoenoic FAs rose by 5 times. The revealed differences in the FA composition of lipids in birch were considered as an indicator of adverse effect of cadmium on the structure and functions of chloroplasts and therefore on photosynthesis.     

Fatty acids of lipids from cultured soybean and rape cells

Lipids from cultured cells, leaves and seeds of two varieties each of soybean (Glycine max) and oil seed rape (Brassica napus) were separated into neutral lipids, glycolipids and phospholipids and their fatty acids were analysed. Usually, the fatty acid composition differed between corresponding fractions from cultured cells, leaves and seeds. Differences were least marked in (i) the phospholipids from cultured cells and leaves of soybean and (ii) the neutral lipids from cultured cells and seeds of rape. In the cultured cells, the fatty acid composition of the phospholipids differed from that of the glycolipids and neutral lipids, and fatty acids of chain length greater than C₁₈ comprised a large proportion of the fatty acids of the glycolipids.     

Properties of prolamin in mature and developing rice grain

A procedure was developed for preparing lipid- and phenol-free prolamin directly from IR480-5-9 milled rice (Oryza sativa L.).The preparation consisted mainly of one protein band on analytical and SDS-polyacrylamide disc gel electrophoresis with subunit MW of 17000 and a minor fraction with subunit MW 23000. The prolamin eluted as a single peak on SDS-Sephadex G-75 gel filtration and on DEAE-cellulose column chromatography. Prolamin was poor in lysine, histidine, cystine, and methionine but rich in glutamic acid, tyrosine and proline. In dehulled developing grain of two different rices, changes in the aminogram of the prolamin fraction coincided with the start of endosperm protein body synthesis and the appearance from 7 days after flowering of a second prolamin subunit with MW 23 000.     

Development of formulae for estimating amylose content and resistant starch content based on the pasting properties measured by RVA of Japonica polished rice and starch

We searched for the easy and simple method to measure the novel indicators which reflect not only AAC, but also (RS) based on pasting properties using RVA. Novel indexes such as SB/Con and Max/Fin (Maximum viscosity/Minimum viscosity) ratios had a very high correlation with proportion of intermediate and long chains of amylopectin; Fb₁₊₂₊₃ (DP ≧ 13). In Japonica polished rice, estimation formulae for AAC and RS content were developed using novel indexes based on pasting properties by RVA, and these equations showed determination coefficients of 0.89 and 0.80 for calibration and 0.71 and 0.75 for validation test. We developed the estimation formulae for AAC and RS content for Japonica starch samples. These equations showed determination coefficients of 0.86 and 1.00 for calibration and 0.76 and 0.83 for validation test, which showed that these equations can be applied to the unknown rice samples.     

Cellular and chloroplast lipid composition of the leaves of Mimosa pudica

Cellular and chloroplast lipids of the leaves of Mimosa pudica have been analysed. Qualitatively the total lipid composition of this plant is similar to that reported for the photosynthetic tissues of other plants. Chloroplast lipids show some resemblance to those of algae. The cerebroside fraction of both leaves and chloroplasts contains a polyunsaturated fatty acid (20:4ω3) and a long chain sphingosine base whose R_f value coincides with that from ox brain cerebroside and not with that of phytosphingosine from spinach.     

Content and composition of phosphoglycerols and neutral lipids at different developmental stages of the eggs of the codling moth,Cydia pomonella (Lepidoptera: Tortricidae)

Phosphoglycerol, triacylglycerol, diacylglycerol, and free fatty acid content was studied in eggs of the codling moth Cydia pomonella at the white, red ring, and black head developmental stages. The composition of total phosphoglycerols and of the three classes of neutral lipids was also analyzed. The highest total lipid content was found in eggs at the white stage, the amount decreasing during development mainly as a result of a diminution in the quantity of phosphoglycerols, which account for approximately 50% of total content at all stages of egg development. The amount of triacylglycerols and free fatty acids changes significantly during development, whereas only minor changes were found in diacyglycerol levels. The total phosphoglycerol acyl composition of eggs at the white and red ring stages is similar, whereas differences are evident at the black head stage of development. Triacylglycerols and free fatty acids are enriched in saturated fatty acids in all analyzed stages. The acyl profile of diacylglycerols is different at each stage. The unsaturation index decreases in diacylglycerols and free fatty acids as a function of egg development. The results of the present paper suggest that triacylglycerols may constitute an important source of energy during the final period of egg development while phosphoglycerols may function as fuel during the beginning. Phosphoglycerols could be precursors for the triacylglycerol biosynthesis that takes place between white and red ring stages.     

Disbalance of the natural ratio of cations in water as a factor affecting synthesis of lipids and fatty acids in fish eggs

The effects on the lipid status of developing embryos of a disturbed natural ratio of cations in water as a result of the pollution of water bodies by waste with a high potassium content (130–140 mg/l) were studied in the laboratory. The results obtained confirm the indication of reduced lipid synthesis and altered formation of phospholipids in embryos developing in a medium with a disturbed natural ratio of cations. In addition, the lysophospholipid fraction increased in these embryos, which indicates activation of phospholipid hydrolysis. It was also found that changes in the salt regime lead to a decreased content of cholesterol, the main membrane thickener. It was proposed that the changes discovered lead to disturbed stability and permeability of the membranes of fish eggs, with the subsequent death of embryos.     

Effect of long term feeding of rice bran oil upon lipids and lipoproteins in rats

The effects of feeding two levels of rice bran oil (RBO) on the growth, lipid parameters, and fatty acid composition of the plasma and liver of rats (Wistar strain) were compared with those produced on animals which had been fed the same levels of peanut oil (PNO). The control animals were fed synthetic diets containing 5 and 20% peanut oil (PNO) and the experimental groups were fed similar diets, containing the same level of rice bran oil (RBO). There was no significant difference with respect to the organ weights between the control and the experimental groups. In general, groups fed 20% oil gained more weight than groups fed 5% oil. The animals which received rice bran oil in their diet had, in general, comparatively lower levels of cholesterol, triglycerides and phospholipids. On the other hand, animals receiving 20% rice bran oil in their diet, showed an increase of 20% in high density lipoproteins (HDL-C), within 18 weeks (p<0.05), when compared to the animals fed with peanut oil. Similarly, low density lipoprotein cholesterol (LDL-C) and very low density lipoprotein cholesterol (VLDL-C) were lower in RBO-fed groups, than in the PNO-fed groups. There was, however, no significant differences in the cholesterol/phospholipid (C/P) ratio of the two groups. Analysis of plasma and of liver fatty acids indicated, in a general way, the type of fat consumed. There were no significant difference in the P/S ratio, nor any in the oleic/linoleic, oleic/stearic, palmitoleic/palmitic, oleic/palmitic, and oleic/palmitoleic ratios. Furthermore, levels of saturated (SAFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids were identical in both the groups. Thus, our results suggest that feeding a high level of rice bran oil (RBO) has no deleterious effect on the growth and blood lipid profile of rats.Abbreviations PNO peanut oil - RBO rice bran oil - HDL-C high density lipoprotein cholesterol - LDL-C low density lipoprotein cholesterol - VLDL-C very low density lipoprotein cholesterol - SAFA saturated fatty acids - MUFA mono-unsaturated fatty acids     

Changes in the composition and content of lipids in the leaves of radish plants of different magnetic orientation induced by weak permanent magnetic field

The effect of weak permanent horizontal magnetic field (PMF) with the intensity of 403 A/m on the composition and content of polar and neutral lipids and their constituent FAs was investigated in the leaves of radish plants (Raphanus sativus L., var. radicula D.C.), cv. Rozovo-krasnyi s belym konchikom, which belong to two major types of magnetic orientation (TMO): North-South (NS) and West-East (WE), with the planes of the root grooves oriented along and across the magnetic meridian, respectively. In spring, PMF reduced the level of total lipids in the NS plants and elevated it in the WE plants; in autumn, the content of total lipids in the NS plants increased in the NS plants and decreased in the WE plants. In spring, the ratio between phospholipids and sterols, which indirectly points to enhanced fluidity of membrane lipid bilayer, increased in the plants of both TMOs, while in autumn, it increased only in the NS plants. In the control plants, the relative content of unsaturated FAs, including linolenic and linoleic acids, was greater in the WE plants than in the NS plants. PMF elevated the content of FAs in the leaves of the NS plants and did not affect their level in the WE plants. It was concluded that weak horizontal PMF differently (and sometimes oppositely) affected the content of lipids in the leaves of the NS and WE radish plants, apparently due to their different sensitivity to the effect of the magnetic field associated with their physiological status.     

Free and bound lipids of Neurospora crassa

Extraction of light and dark grown cells of Neurospora crassa with chloroform-methanol gave a free lipid extract in which the relative amounts and compositions of sterols, fatty acid and carotenoid fractions were determined. Further extraction of the cells with methanolic potassium hydroxide solution liberated a bound lipid fraction from the cells. The levels of the bound lipid fraction were much lower than those of the free lipids but analysis showed that the composition was similar to that of the free lipids.     

Modulation of amylose content by structure‐based modification of OsGBSS1 activity in rice (Oryza sativa L.)

The rice Waxy (Wx) gene encodes granule‐bound starch synthase 1 (EC 2.4.1.242), OsGBSS1, which is responsible for amylose synthesis in rice seed endosperm. In this study, we determined the functional contribution of eight amino acids on the activity of OsGBSS1 by introducing site‐directed mutated Wx gene constructs into the wx mutant glutinous rice. The eight amino acid residues are suspected to play roles in OsGBSS1 structure maintenance or function based on homologous enzyme sequence alignment and homology modelling. Both OsGBSS1 activity and amylose content were analysed in homozygous transgenic lines carrying the mutated OsGBSS1 (Wx) genes. Our results indicate that mutations at diverse sites in OsGBSS1 reduces its activity by affecting its starch‐binding capacity, its ADP‐glucose‐binding capability or its protein stability. Our results shed new light on the structural basis of OsGBSS1 activity and the mechanisms of OsGBSS1 activity on amylose synthesis in vivo. This study also demonstrates that it is feasible to finely modulate amylose content in rice grains by modifying the OsGBSS1 activity.     

Neutral lipids of leaves and stems of Trifolium repens

The neutral lipids of white clover leaves and stems have been separated into wax esters, free fatty acids, free fatty alcohols, free sterols, triglycerides and hydrocarbons. The wax esters were mainly of C₁₈ di- and tri-unsaturated fatty acids and C₃₀ fatty alcohol. Linolenic acid was the predominant free fatty acid and triacontanol was the principal free fatty alcohol. Of the hydrocarbons, C₂₉ and C₃₁ were present in the largest amounts.     

Antisense regulation of the rice waxy gene expression using a PCR-amplified fragment of the rice genome reduces the amylose content in grain starch

The waxy gene encodes a granule-bound starch synthase. A 1.0-kb portion of the sequence of the rice waxy gene, which includes the region between exon 4 and exon 9, was inserted in an antisense orientation between the 35 S promoter and the GUS gene of pBI221. The resultant plasmid, pWXA23, was introduced into rice protoplasts by electroporation. GUS activity was clearly detected in derived callus lines, suggesting that the antisense component of the fusion gene was also expressed. Transgenic rice plants were regenerated from these callus lines and their GUS activity was confirmed. Some of the rice seeds from these transformants showed a significant reduction in the amylose content of grain starch, even though they had become polyploid. These results suggest that even when intron sequences are included, antisense constructs can bring about a reduced level of expression of a target gene. The utility of GUS, included as a reporter gene, for the simple detection of expression of an antisense gene, was apparent from these results.     

Effect of carbon dioxide enrichment on chlorophyll content, starch content and starch grain structure in Trifolium subterraneum leaves

Trifolium subterraneum (cv. Dinninup) responds to enriched atmospheric CO₂ in a manner similar to that described by Madsen (1968 and 1976) for tomato. In immature leaves, the total chlorophyll content per unit dry weight and the chlorophyll a:b ratio are significantly lower in plants grown at 0.10 vol% CO₂. Although fully expanded mature leaves partially overcome the deficit in chlorophyll content, the chlorophyll a:b ratio remains substantially lower in these high CO₂ grown plants. The large amount of starch accumulated as irregularly shaped grains appears to disrupt normal chloroplast structure in clover plants grown in enriched atmospheric CO₂. These results indicate the chlorotic appearance of leaves from high CO₂ grown clover plants is due to a decrease in chlorophyll content per dry weight possibly resulting from large starch grains and starch accumulation altering normal chloroplast structure and function.     

稻米直链淀粉含量测定方法研讨

通过标准碘比色法与改良碘比色法的比较认为改良碘比色法的优点是:既可测定精米粉或糙米粉等粉体材料也可测定精米粒和糙米粒等粒体材料,能将样品的直链淀粉更完全地分离出来,测试误差小,但需时间较长。相同品种不同类型样品直链淀粉的含量测定结果:精米粒>精米粉和糙米粒>糙米粉。测试精米粒或精米粉时宜选择强碱 KOH,而测试糙米粒或糙米粉时宜选择强碱 NaOH。样品量以100mg 为宜,但不足100mg 时进行品种间的比较仍可考虑采用。     

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.     

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

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

Effects of temperature and gibberellic acid on phospholipid composition of Avena sativa stem segments

Stem segments taken from Avena sativa plants grown at 10°, 20° or 30° varied in their phospholipid composition depending on the growth temperature; as temperature was lowered, there was a shift towards a greater proportion of unsaturated fatty acids. A significant increase was observed in the concentration of linolenic acid (18:3) as growth temperature was lowered. Although prolonged treatment of oat plants with GA₃ produced marked changes in phospholipid composition of stem segments, these changes did not always accompany the GA₃-induced growth response of segments. Treatment of stem segments with GA₃ for only 20 hr produced a significant growth response with little or no effect on phospholipid composition over this time. The data support the hypothesis that GA₃-induced growth in Avena stem segments can occur without a concomitant change in phospholipid composition.