含神经酸植物的研究

对自然界中植物果实的含油量、神经酸含量等进行了比较研究。研究结果认为,在目前发现的31种含有神经酸的植物中,蒜头果、盾叶木和遏蓝菜果实含油量高、且富含神经酸,是目前较为理想的开发神经酸产品的植物资源。     

植物神经酸研究进展

神经酸是一种超长链单不饱和脂肪酸,最初发现于哺乳动物神经组织中,是脑部神经组织和神经细胞的天然核心成分,具有修复受损神经纤维、帮助神经细胞再生的功能。神经酸的来源由动物到植物的转变极大地促进了神经酸的研究。近年来,国内外科学家尝试通过转基因技术进行高神经酸植物的遗传改良。含神经酸的油菜在神经酸植物来源中脱颖而出,有望解决神经酸短缺的现状。综述了植物中神经酸的生理功能和来源,介绍了植物中神经酸的生物合成途径和从植物中提取神经酸的工艺,以期为植物神经酸相关研究和油菜创新育种提供理论参考。     

湖北省23种植物油脂分析

本文报道了湖北省15个科中23种植物油脂的含油量、碘值、皂化值,以及用气相色谱法,对它们常见脂肪酸组成的定量分析结果。我们自承担“全国植物油脂研究”课题以来,对湖北省野生油脂植物资源进行了广泛的调查,收集了有关植物的果实和种子,进行了109种植物油脂的含油量、碘值、皂化值和常见脂肪酸的测定。后又到神农架等地对15个科23种植物油脂作了进一步的调查研究和分析。其中13种植物油脂数据在国内外尚未见报道。     

沙棘果实发育过程中内源激素水平的动态变化

沙棘(Hippophae rhamnoides)是荒漠化防治和水土保持的重要经济树种, 其果实中含有丰富的生物活性成分。内源激素生长素(IAA)、赤霉素(GA₄)、脱落酸(ABA)和茉莉酸(JA)在沙棘果实发育过程中起着重要的调控作用, 但不同发育期内源激素的动态变化及其对果实生长发育的影响仍不清楚。以亲缘关系近且含油量差异明显的2个沙棘品系不同发育期果实为材料, 利用液相色谱串联质谱法检测了4种内源激素含量的动态变化。结果表明, 在果实发育过程中, 80%–85%的含水量有利于内源激素浓度的相对稳定; 果实含油量在不同发育期增速基本一致, 2个品系含油量在中后期开始出现明显差异。IAA和JA含量在果实成熟过程中呈先高后低的趋势; ABA含量在果实发育中后期始终处于较高水平; 而GA₄含量一直处于较低水平。高ABA/GA₄有利于果实油脂的合成与积累。研究结果为揭示不同内源激素对沙棘果实发育的调节作用提供了理论依据。     

车八岭国家级自然保护区油脂植物资源

油脂植物广泛存在于植物界,它们的果实、种子、花粉、孢子、茎、叶、根等器官都含有油脂,尤其以种子含油量最丰富.油脂植物是构成车八岭国家级自然保护区生物多样性重要组成部分,初步调查,车八岭国家级自然保护区共有油脂植物55科96属144种.车八岭保护区内野生油脂种类繁多,资源丰富,能适应多种需求,具有无法估计的生态和经济价值.目前对野生油脂植物开发利用较少,经营比较粗放,许多资源尚未得到利用,建议进一步开展油脂植物研究,查清油脂植物的分布特点、主要油脂植物的特点以及可开发利用性、资源蕴藏量,以便制定科学利用计划,引导当地群众合理利用区内的油脂植物资源,可增加农民收入,促进农村经济发展,减轻对林木资源的依赖.     

江西省樟科富油能源植物的开发利用研究

樟科是一个富油能源植物重点科。通过文献查阅、野外考察和种子实测, 结果表明: 江西省樟科植物共有14 属89种, 其中种子含油量在60%以上的有6种; 含油量在50%-60%的有14种, 含油量在30%-50%有7种; 从油脂价值、经济价值、生态价值和资源潜力等方面进行综合评价, 表明: 大叶新木姜、鸭公树、山鸡椒、木姜子、黑壳楠、月桂、鳄梨、阴香、樟、黄樟、潺槁等11种优良能源植物, 值得开发利用和推广种植。尤其是大叶新木姜、鸭公树、山鸡椒, 其分布广, 适应性强, 果实大, 易采摘, 且单株产量高而极具开发前景。     

茉莉酸信号及其在木本植物中的研究进展

茉莉酸作为一种重要的植物内源激素,广泛参与植物生长发育调控、防御反应、开花时间调节及花发育进程等生物学过程.此外,茉莉酸可以介导果实品质和调节植物体内代谢物含量,在农林经济生产中具有重要作用.针对近年来茉莉酸信号领域取得的研究进展,本文总结了茉莉酸信号在植物胁迫响应、防御反应、开花时间调控、花器官发育、色泽品质和代谢成分变化中的作用及信号转导机制,并阐述了茉莉酸信号在木本植物生长发育中的功能及机制.提出在木本植物中研究茉莉酸信号途径,应扩大茉莉酸通路中关键因子的互作蛋白筛选,同时兼顾茉莉酸与其他激素信号转导途径间的交叉关系,考虑不同品种、不同基因型之间的差异,以充分揭示茉莉酸信号调控途径的多样性和转导机制的复杂性,挖掘其在林木中的潜在功能.     

中国植物油脂的研究Ⅰ——一百种植物种子油的脂肪酸成分

本文根据我国一百种油脂植物(隶41科,71属的种子或果实,进行了含油量、折光率、比重、皂化值、碘值等理化常数的测定,运用气相色谱仪对它们的常见脂肪酸进行了定量。 根据分析结果,本文着重讨论了在菊科、安息香料、木樨科、茶科、樟科和藤黄科油脂植物中各种常见的饱和脂肪酸和不饱和脂肪酸的含量及其利用价值。     

白刺果实化学成分的分析测定

白刺果实化学成分的分析测定赵长琦，李华，张小燕，梁萍，刘丽娜（西北大学生物系，分析测试研究中心７１００６９）白刺（Ｎｉｔｒａｒｉａｔａｎｇｕｔｏｒｕｍ），又名酸胖，为蒺藜科白刺属植物。其果实常入药。主要分布在我国西北部干旱少雨的沙漠地区。因其植物本身...     

影响农杆菌介导的麻疯树基因转化因素的研究(简报)

麻疯树(Jatropha curcas)为大戟科麻疯树属植物,是一种多年生木本油料植物。原产美洲,广泛分布于热带亚热带地区。因其种子含油量高达 60％,可作生物燃料之用,麻疯树是目前正在被开发利用的重要能源植物之一。除此之外,麻疯树的种子含有多种活性成分,有着重要的农药和医药价值;其生长能耐干旱贫瘠,可用于荒山造林。因此,麻疯树是一种具有多种用途、重要经济价值和学术研究价值的植物。目前对其研究多停留在植物组织培养、植物化学、毒理学、种植业方面等。     

Molecular cloning and characterization of a KCS gene from Cardamine graeca and its heterologous expression in Brassica oilseeds to engineer high nervonic acid oils for potential medical and industrial use

Nervonic acid 24:1 Δ15 ( cis -tetracos-15-enoic acid) is a very long-chain monounsaturated fatty acid and exists in nature as an elongation product of oleic acid. There is an increasing interest in production of high nervonic acid oils for pharmaceutical, nutraceutical and industrial applications. Using a polymerase chain reaction approach, we have isolated a gene from Cardamine graeca L., which encodes a 3-ketoacyl-CoA synthase (KCS), the first component of the elongation complex involved in synthesis of nervonic acid. Expression of the Cardamine KCS in yeast resulted in biosynthesis of nervonic acid, which is not normally present in yeast cells. We transformed Arabidopsis and Brassica carinata with the Cardamine KCS under the control of the seed-specific promoter, napin. The T₃ generations of transgenic Arabidopsis and B. carinata plants expressing the Cardamine KCS showed that seed-specific expression resulted in relatively large comparative increases in nervonic acid proportions in Arabidopsis seed oil, and 15-fold increase in nervonic acid proportions in B. carinata seed oil. The highest nervonic acid level in transgenic B. carinata lines reached 44%, with only 6% of residual erucic acid. In contrast, similar transgenic expression of the Cardamine KCS in high erucic B. napus resulted in 30% nervonic acid but with 20% residual erucic acid. Experiments using the Lunaria KCS gene gave results similar to the latter. In both cases, the erucic acid content is too high for human or animal consumption. Thus, the Cardamine KCS: B. carinata high nervonic/highly reduced erucic transgenic seed oils will be the most suitable for testing in pharmaceutical/nutraceutical applications to improve human and animal health.     

Synthesis and characterization of poly(3-hydroxyalkanoates) from Brassica carinata oil with high content of erucic acid and from very long chain fatty acids

Pseudomonas aeruginosa produced medium chain length poly(3-hydroxyalkanoates) (mcl-PHAs) when grown on substrates containing very long chain fatty acids (VLCFA, C>20). Looking for low cost carbon sources, we tested Brassica carinata oil (erucic acid content 35-48%) as an intact triglyceride containing VLCFA. Oleic (C18:1), erucic (C22:1), and nervonic (C24:1) acids were also employed for mcl-PHA production as model substrates. The polymers obtained were analyzed by GC of methanolyzed samples, GPC, 1H and 13C NMR, ESI MS of partially pyrolyzed samples, and DSC. The repeating units of such polymers were saturated and unsaturated, with a higher content of the latter in the case of the PHA obtained from B. carinata oil. Statistical analysis of the ion intensity in the ESI mass spectra showed that the PHAs from pure fatty acids are random copolymers, while the PHA from B. carinata oil is either a pure polymer or a mixture of polymers. Weight-average molecular weight varied from ca. 56,000 g/mol for the PHA from B. carinata oil and oleic acid, to about 120,000 g/mol for those from erucic and nervonic acids. The PHAs from erucic and nervonic acids were partially crystalline, with rubbery characteristics and a melting point (Tm) of 50°C, while the PHAs from oleic acid and from B. carinata oil afforded totally amorphous materials, with glass transition temperatures (Tg) of -52°C and -47°C, respectively.     

Intertribal somatic hybrids between Brassica napus and Thlaspi perfoliatum with high content of the T. perfoliatum-specific nervonic acid

Protoplast fusions were performed between hypocotyl protoplasts of Brassica napus and mesophyll protoplasts of Thlaspi perfoliatum. The two species are members of the Lepidieae and Brassiceae tribes, respectively, in the family of Brassicaceae. Seeds of T. perfoliatum are rich in the fatty acid C₂₄₁ (nervonic acid), an oil valuable for technical purposes. In the search for renewable oils to replace the mineral oils, plant breeders have been trying to develop oil crops with a high content of long-chain fatty acids. After fusion of B. napus protoplasts with non-irradiated as well as irradiated protoplasts of T. perfoliatum selection was carried out by flow cytometry and cell sorting. Of the shoots regenerated from different calli 27 were verified as hybrids or partial hybrids using the isoenzyme phosphoglucose isomerase (PGI) as a marker. Another 6 plants were identified as partial hybrids using a T. perfoliatum-specific repetitive DNA sequence. Slot blot experiments were performed to estimate the copy number of the repetitive DNA sequence in the parental species and in the hybrids. In T. perfoliatum there were approximately 10⁵ copies per haploid genome, and the range in the hybrids was 1–37% of the value in T. perfoliatum. When the nuclear DNA content of the regenerated shoots was analysed we found partial as well as symmetric hybrids. Even though the rooting and establishment of hybrid shoots in the greenhouse were difficult, resulting in the death of many plants, 19 plants were cultured to full maturity. Seeds obtained from 15 plants were analysed to determine whether they contained nervonic acid, and 5 of the hybrids were found to contain significantly greater amounts of nervonic acid than B. napus.     

Effect of alcohol on the metabolic conversion of 14C erucic acid in the liver of rats receiving rapeseed or peanut oil]

The effects of addition of ethanol to diets containing rapeseed or ground nut oil on the metabolic conversions of 14 14C erucic and 9-10 3H oleic acid were studied in the rat liver. 1. Whatever the diet more 14C than 3H radioactivity was recovered in liver lipids 2 and 19 hours after injection of labelled fatty acids. Ethanol has little effect on this incorporation. 2. Only small amounts of 3H oleic acid were converted. 3. In all cases, the metabolic conversion of erucic acid was identical: the main part of 14C was not recovered as erucic acid but was present in other monounsaturated fatty acids n-9: oleic acid (18 : 1), which was the most labelled acid, 16 : 1, 20 : 1 and nervonic acid (24 : 1). 4. The amount of erucic acid converted to shorter chain fatty acids was unchanged by addition of ethanol but the alcohol increased the proportion of 14C radioactivity recovered as nervonic acid. This latter effect was opposite to the effect of rapeseed oil diet, which consisted in a decrease in the conversion of erucic to nervonic acid. 5. A high amount of 14C radioactivity was recovered in the F.F.A. fraction of the liver as an unknown compound (13 and 80% of 14C radioactivity respectively after 2 and 19 h.) Its identification is presently under investigation.     

湘西南龙底自然保护区油料植物组成与资源价值分析

分析了龙底自然保护区油料植物组成与资源特点。结果表明：（1）油料植物107科281属477种,其中精油植物131种,樟科（7属27种）、芸香科（6属21种）、唇形科（11属17种）等11个科为优势科,以木本植物为主,占73.38%。（2）以种子种皮为主要含油部位的植物占71.47%,植物含油量＞20.0%的有211种,＞50.0%的43种;油脂脂肪酸含量＞70.0%的有7科11种,亚油酸含量＞70.0%的有12科20种。（3）在精油植物中,57种植物含精油量＞1.0%,13种＞4.0%。龙底自然保护区内油料植物资源丰富,特别是富油植物资源种类较多,是油料植物富集之地,具开发利用潜力。     

Incorporation of Very-Long-Chain Fatty Acids into Sphingolipids of Cultured Neural Cells

We examined effects of exogenous very-long-chain fatty acids on lipids of cultured chick neurons and astrocytes. When chick neurons were incubated in chemically defined medium containing 10 microM nervonic acid (C24:1) for 7 days, it was found that a major fatty acid moiety of gangliosides and sphingomyelin was nervonic acid itself, which was not normally detected in the sphingolipid fraction. This alteration in the fatty acid composition apparently occurred in each ganglioside species. Under these experimental conditions, nervonic acid was not found in the glycerophospholipid fraction, and the amounts of triacylglycerol and free nervonic acid increased. Addition of behenic acid (C22:0) or erucic acid (C22:1) also induced changes in the fatty acid composition of gangliosides. When chick astrocytes were incubated in the presence of 10 microM nervonic acid for 7 days, no significant change was observed in the fatty acid composition of gangliosides. These studies indicate that the manipulation of the fatty acid moiety of sphingolipids in cultured neurons is possible.     

Modification of the fatty acid composition of Ehrlich ascites tumor cell plasma membranes

The fatty acyl group composition of Ehrlich ascites tumor cell plasma membranes was modified by feeding the tumor-bearing mice diets rich in either coconut or sunflower oil. When coconut oil was fed, the oleate content of the membrane phospholipids was elevated and the linoleate content reduced. The opposite occurred when sunflower oil was fed. Qualitatively similar changes were observed in the plasma membrane phosphatidylethanolamine, phosphatidylcholine and mixed phosphatidylserine plus phosphatidylinositol fractions. These diets also produced differences in the sphingomyelin fraction, particularly in the palmitic and nervonic acid contents. Unexpectedly, the saturated fatty acid content of the plasma membrane phospholipids was somewhat greater when the highly polyunsaturated sunflower oil was fed. The small quantities of neutral lipids contained in the plasma membrane exhibited changes in acyl group composition similar to those observed in the phospholipids. These fatty acyl group changes were not accompanied by any alteration in the cholesterol or phospholipid contents of the plasma membranes. Therefore, the lipid alterations produced in this experimental model system are confined to the membrane acyl groups.     

Modification of the fatty acid composition of Ehrlich ascites tumor cell plasma membranes.

The fatty acyl group composition of Ehrlich ascites tumor cell plasma membranes was modified by feeding the tumor-bearing mice diets rich in either coconut or sunflower oil. When coconut oil was fed, the oleate content of the membrane phospholipids was elevated and the linoleate content reduced. The opposite occurred when sunflower oil was fed. Qualitatively similar changes were observed in the plasma membrane phosphatidylethanolamine, phosphatidylcholine and mixed phosphatidylserine plus phosphatidylinositol fractions. These diets also produced differences in the sphingomyelin fraction, particularly in the palmitic and nervonic acid contents. Unexpectedly, the saturated fatty acid content of the plasma membrane phospholipids was somewhat greater when the highly polyunsaturated sunflower oil was fed. The small quantities of neutral lipids contained in the plasma membrane exhibited changes in acyl group composition similar to those observed in the phospholipids. These fatty acyl group changes were not accompanied by any alteration in the cholesterol or phospholipid contents of the plasma membranes. Therefore, the lipid alterations produced in this experimental model system are confined to the membrane acyl groups.