Lipid Storage and Utilization in Reptiles

Lipids represent a biochemically efficient mechanism for storingenergy to be used at a later date for maintenance and/or reproduction.This storage and utilization at different times results in seasonalpatterns of lipid cycling. Reptiles exhibit a number of lipidcycling patterns which can be explained by seasonal patternsof food availability. Seasonality in food availability determinesthe quantity of lipids stored, when lipids are stored, and forwhat purposes these lipids are utilized. Lipid cycling patternsare in turn correlated with life histories.     

Biochemical Aspects of Lipid Storage and Utilization in Animals

The high energy content of lipids makes these compounds attractiveto active metazoans as alight form of fuel storage. Animalshave evolved complex systems of enzymes and transport proteinsin order to utilize lipids for the generation of energy. Whilethe enzymatic systems responsible for lipid synthesis and oxidationare probably similar in all metazoans, mechanisms for controlof the rates of these processes differ with taxonomic group.The means by which lipids are transported through the body fluidsof metazoans also show phylogenetic variation. Complete, quantitativedata on the mechanisms and rates of lipid digestion, synthesis,transport and utilization are available for only a very fewmammals, birds and insects. This would seem to be a very fertilefield for comparative physiologists.     

Translocation and Utilization of Fungal Storage Lipid in the Arbuscular Mycorrhizal Symbiosis

The arbuscular mycorrhizal (AM) symbiosis is responsible for huge fluxes of photosynthetically fixed carbon from plants to the soil. Carbon is transferred from the plant to the fungus as hexose, but the main form of carbon stored by the mycobiont at all stages of its life cycle is triacylglycerol. Previous isotopic labeling experiments showed that the fungus exports this storage lipid from the intraradical mycelium (IRM) to the extraradical mycelium (ERM). Here, in vivo multiphoton microscopy was used to observe the movement of lipid bodies through the fungal colony and to determine their sizes, distribution, and velocities. The distribution of lipid bodies along fungal hyphae suggests that they are progressively consumed as they move toward growing tips. We report the isolation and measurements of expression of an AM fungal expressed sequence tag that encodes a putative acyl-coenzyme A dehydrogenase; its deduced amino acid sequence suggests that it may function in the anabolic flux of carbon from lipid to carbohydrate. Time-lapse image sequences show lipid bodies moving in both directions along hyphae and nuclear magnetic resonance analysis of labeling patterns after supplying 13C-labeled glycerol to either extraradical hyphae or colonized roots shows that there is indeed significant bidirectional translocation between IRM and ERM. We conclude that large amounts of lipid are translocated within the AM fungal colony and that, whereas net movement is from the IRM to the ERM, there is also substantial recirculation throughout the fungus.     

Lysosomal Lipid Storage Diseases

Lysosomal lipid storage diseases, or lipidoses, are inherited metabolic disorders in which typically lipids accumulate in cells and tissues. Complex lipids, such as glycosphingolipids, are constitutively degraded within the endolysosomal system by soluble hydrolytic enzymes with the help of lipid binding proteins in a sequential manner. Because of a functionally impaired hydrolase or auxiliary protein, their lipid substrates cannot be degraded, accumulate in the lysosome, and slowly spread to other intracellular membranes. In Niemann-Pick type C disease, cholesterol transport is impaired and unesterified cholesterol accumulates in the late endosome. In most lysosomal lipid storage diseases, the accumulation of one or few lipids leads to the coprecipitation of other hydrophobic substances in the endolysosomal system, such as lipids and proteins, causing a “traffic jam.” This can impair lysosomal function, such as delivery of nutrients through the endolysosomal system, leading to a state of cellular starvation. Therapeutic approaches are currently restricted to mild forms of diseases with significant residual catabolic activities and without brain involvement.Lysosomal lipid storage diseases are a group of inherited catabolic disorders in which typically large amounts of complex lipids accumulate in cells and tissues. Macromolecules such as complex lipids and oligosaccharides are constitutively degraded in the acidic compartments of the cell, the endosomes, and lysosomes, into their building blocks. The resulting catabolites are exported to the cytosol and reused in cellular metabolism. When lysosomal function is impaired because of a defect in a catabolic step, degradation cannot proceed normally and undegraded compounds accumulate. Lysosomal lipid storage diseases comprise mainly the sphingolipidoses, Niemann-Pick type C disease (NPC), and Wolman disease, including the less severe form of this disease, called cholesteryl ester storage. NPC is a complex lipid storage disease mainly characterized by the accumulation of unesterified cholesterol in the late endosomal/lysosomal compartment (Bi and Liao 2010). The sphingolipidoses are caused by defects in genes encoding proteins involved in the lysosomal degradation of sphingolipids (Kolter and Sandhoff 2006). First reports on these diseases were given more than a century ago. Already in 1881, Warren Tay described the clinical symptoms of a disease, which is today called Tay-Sachs disease (Tay 1881). After Christian de Duve discovered the lysosome in 1955 (de Duve 2005), Henri-Géry Hers established the first correlation between an enzyme deficiency and a lysosomal storage disorder (Pompe’s disease) in 1963 (Hers 1963). In the following decades, the enzymes and cofactors deficient in the sphingolipidoses have been identified. Though lysosomal lipid storage diseases have been known for a long time, treatment is only available for a few mild forms of the diseases, such as the adult forms of Gaucher disease (Barton et al. 1991). For several lysosomal storage diseases, therapies like enzyme replacement or bone marrow transplantation are in the clinical trial stage (Platt and Lachmann 2009). For a long time, lysosomal diseases have been considered a problem of superabundance (storage) in which the storage material can slowly spread to other cellular membranes, impairing their function. More recently, it came into focus that massive storage prevents lysosomal functions such as nutrition delivery through the endolysosomal system, leading to a state of cellular starvation. In mouse models of both GM1 and GM2 gangliosidoses iron is progressively depleted in brain tissue. Administration of iron prolonged survival in the diseased mice by up to 38% (Jeyakumar et al. 2009).     

Physical-Chemical Characterization and Formulation Considerations for Solid Lipid Nanoparticles

Pure glyceryl mono-oleate (GMO) (lipid) and different batches of GMO commonly used for the preparation of GMO-chitosan nanoparticles were characterized by modulated differential scanning calorimetry (MDSC), cryo-microscopy, and cryo-X-ray powder diffraction techniques. GMO-chitosan nanoparticles containing poloxamer 407 as a stabilizer in the absence and presence of polymers as crystallization inhibitors were prepared by ultrasonication. The effect of polymers (polyvinyl pyrrolidone (PVP), Eudragits, hydroxyl propyl methyl cellulose (HPMC), polyethylene glycol (PEG)), surfactants (poloxamer), and oils (mineral oil and olive oil) on the crystallization of GMO was investigated. GMO showed an exothermic peak at around ?10°C while cooling and another exothermic peak at around ?12°C while heating. It was followed by two endothermic peaks between 15 and 30 C, indicative of GMO melting. The results are corroborated by cryo-microscopy and cryo-X-ray. Significant differences in exothermic and endothermic transition were observed between different grades of GMO and pure GMO. GMO-chitosan nanoparticles resulted in a significant increase in particle size after lyophilization. MDSC confirmed that nanoparticles showed similar exothermic crystallization behavior of lipid GMO. MDSC experiments showed that PVP inhibits GMO crystallization and addition of PVP showed no significant increase in particle size of solid lipid nanoparticle (SLN) during lyophilization. The research highlights the importance of extensive physical-chemical characterization for successful formulation of SLN.     

种子萌发过程中贮藏油脂的动员

对植物种子萌发过程中贮藏油脂动员的研究进展进行了综述。不同种子的贮藏油脂的降解途径不同。目前提出有3条途径:传统的脂酶直接水解途径;新近发现的酰基-CoA-二酯酰甘油酰基转移酶途径和脂氧合酶(LOX)途径。前两条途径不依赖于LOX。这3条途径可能在贮藏油脂动员过程中是并存的,但目前尚不知道在种子萌发过程中油脂降解是以那一条降解途径为主,以及不同的种之间是否存在差异。此外,3条降解途径目前都缺乏分子生物学的直接证据。     

秀丽线虫脂肪积累调控的生理与分子机制

脂肪积累是一个复杂的生理过程,模式动物秀丽线虫(以下简称线虫)已经成为目前研究脂肪积累的重要模型.线虫中的脂肪酸代谢通路与其他物种中的代谢是基本一致的,很多关键的代谢调节基因的功能已经得到鉴定.线虫中脂肪积累涉及至少4个核心调控通路,分别为胰岛素和转化生长因子β(TGF-β)信号通路、sbp-1/ mdt-15介导的信号通路、核激素受体nhr-49介导的信号通路与雷帕霉素靶标(TOR)和氨基己糖介导的信号通路.此外,神经递质5-羟色胺、多巴胺和谷氨酸参与了脂肪积累的调控,而tub-1和bbs-1可以介导对脂肪积累的神经调控,暗示了纤毛结构与感觉神经元在脂肪积累中可能的重要功能.线虫中的研究工作对人类肥胖症等代谢疾病的研究具有重要的提示作用.     

Some Physiological Parameters and Seed Lipid Composition of Transgenic Tobacco Plant

To see the effects of foreign gene introduction on the physiological performance and the quality and quantity of seed lipids, we studied transgenic tobacco plant as a model system, as tobacco seeds are oil seeds. Using Agrobacterium Ti plasmid based vectors, tobacco plants cv Petit Havana were transformed by NPT II gene as selectable marker. Transformed T₀ generation plants raised in tissue culture were transferred to pots and selfed. From the seeds, T₁ generation plants were grown in pots and their physiological performance was assessed. The transgenic plants showed slightly slower rates of germination and growth. Total chlorophyll content, chlorophyll a/b ratio and specific leaf weight, however, remained unchanged. The transgenic plants also had delayed flowering. However, total protein, lipid content and fatty acid composition of lipids of seeds in transgenic plants did not show appreciable difference from the seeds from control plants. Thus the physiological cost of transgenic plant for the extra genetic load was only marginal, if any.     

Design Considerations for Unconventional Electrochemical Energy Storage Architectures

Batteries have become fundamental building blocks for the mobility of modern society. Continuous development of novel battery chemistries and electrode materials has nourished progress in building better batteries. Simultaneously, novel device form factors and designs with multi‐functional components have been proposed, requiring batteries to not only integrate seamlessly to these devices, but to also be a multi‐functional component for a multitude of applications. Thus, in the past decade, along with developments in the component materials, the focus has been shifting more and more towards novel fabrication processes, unconventional configurations, and additional functionalities. This work attempts to critically review the developments with respect to emerging electrochemical energy storage configurations, including, amongst others, paintable, transparent, flexible, wire or cable shaped, ultra‐thin and ultra‐thick configurations, as well as hybrid energy storage‐conversion, or graphene‐incorporated batteries and supercapacitors. The performance requirements are elaborated together with the advantages, but also the limitations, with respect to established electrochemical energy storage technologies. Finally, challenges in developing novel materials with tailored properties that would allow such configurations, and in designing easier manufacturing techniques that can be widely adopted are considered.     

种子的贮油细胞器——油体及其蛋白

生物柴油作为一种可再生的替代能源,因其良好的环境效应而倍受关注.植物油是生产生物柴油的主要原料.植物油作为最经济、最有利于种子传播和萌发生长的能量和碳源物质,贮存和积累于植物种子的贮油细胞器-油体之中.本文综述了植物种子油体的亚细胞结构、化学组成及其功能、生物合成与降解等的研究进展.     

种子的贮油细胞器——油体及其蛋白

生物柴油作为一种可再生的替代能源, 因其良好的环境效应而倍受关注。植物油是生产生物柴油的主要原料。植物油作为最经济、最有利于种子传播和萌发生长的能量和碳源物质, 贮存和积累于植物种子的贮油细胞器——油体之中。本文综述了植物种子油体的亚细胞结构、化学组成及其功能、生物合成与降解等的研究进展。     

Storage Lipid Accumulation by Zygotic and Somatic Embryos in Culture

In vitro accumulation of storage lipids occurs in zygotic andsomatic embryos of Brassicu napus L. The concentration of sucrosein the medium modified the pattern of storage lipid accumulationin zygotic and somatic embryos. The sucrose concentration atwhich the maximum amount of lipid is accumulated by the twotypes of embryos is different Analysis of fatty acid compositionshowed that the same fatty acids are present in embryos in vivoand those cultured in vitro although there are quantitativedifferences. The possibility of using this type of system forin vitro production of valuable plant metabolites is discussed Embryo cloning, somatic embryogenesis, in cilro culture, storage lipids, Brussica napus, oilseed rape     

Fatty Acid Compositions of Rice Lipid and their Changes during Storage

Fatty acid composition of lipids from polished rice was studied by gas chromatography on the separated fractions, fat-by-hydrolysis, neutral fat, free fatty acid and phospholipid. After six months storage, fatty acids were released from neutral fat in the same proportion as they were combined in the neutral fat.     

不同贮藏条件对马铃薯微型种薯活力及生理特性的影响

以‘大西洋’、‘夏波蒂’2个品种的脱毒微型种薯为试验材料,分别在冷藏(4~6℃)、窖藏(8~12℃)和常温(18~22℃)条件下贮藏110 d,研究不同贮藏条件和温度对马铃薯微型种薯活力及生理特性的影响。结果表明:(1)低温冷藏能显著提高微型种薯的活力,2个品种的活力指数分别比窖藏和常温贮藏高20.44%、20.28%和33.51%、35.46%。(2)冷藏与窖藏和常温贮藏相比,CAT活性高35.37%~48.25%、91.68%~125.23%,SOD活性高5.79%~6.60%、10.53%~12.81%,而MDA含量却降低30.47%~47.79%、85.54%~87.09%。(3)随着微型种薯的重量增加其活力指数显著提高,CAT和SOD活性也增加,而MDA含量逐渐降低。(4)经不同条件贮藏后,微型种薯的含水量呈下降趋势,以冷藏条件的含水量降低最少;可溶性蛋白含量显著增加,冷藏比窖藏和常温贮藏分别高14.63%~24.67%和25.5%~35.04%;淀粉含量表现为不同程度降低,以窖藏降低最少;可溶性糖含量虽有明显降低,但其含量变化无显著差异。说明低温贮藏可以使马铃薯微型种薯保持较高的活力,适合贮藏条件的顺序依次为:冷藏>窖藏>常温贮藏。     

Cidea和Cidec促进肝脏中脂类的积累

目的:探讨Cidea和Cidec对肝脏中脂滴大小和脂类积累的影响。方法:首先,检测ob/ob肥胖小鼠的脂肪肝中Cidea和Cidec的表达情况。然后,采用腺病毒系统在野生型小鼠肝脏中过表达Cidea和Cidec,以及在ob/ob小鼠肝脏中基因沉默Cidea和Cidec,检测肝脏中脂滴大小和脂积累情况。结果:Cidea和Cidec在脂肪性肝脏中高表达。肝脏细胞中过表达Cidea和Cidec促进大脂滴的形成并能促进小鼠肝脏中的脂积累,且二者有协同作用。在脂肪肝中沉默Cidea和Cidec能缓解脂肪肝的程度,且脂合成基因的下调,线粒体活性增加。Cidea和Cidec的共沉默能进一步降低肝脏中的脂类积累。结论:Cidea和Cidec在促进肝脏的脂积累中起重要作用,并且二者有协同作用。     

脂肪储存小滴蛋白5 重组腺病毒的制备

目的:利用AdEasy腺病毒表达系统构建含有小鼠脂肪储存小滴蛋白5(LSDP5)基因的重组腺病毒。方法:从小鼠肝脏cDNA克隆出LSDP5基因全长,克隆至pMD18-T载体中,酶切测序。回收酶切产物,连接到腺病毒穿梭载体pShuttle-CMV,构建pShuttle-CMV-LSDP5重组质粒,经PmeI酶切线性化后转化至含有腺病毒骨架质粒pAdEasy-1的BJ5183中。筛选阳性克隆,提取重组质粒,PacI酶切线性化并转染AD293细胞进行包装,提取病毒DNA,鉴定重组病毒并检测病毒滴度。结果:LSDP5基因克隆经测序证实与Genebank公布一致,双酶切重组pMD18-T载体得到1400 bp左右的片段。重组穿梭载体经Kpn I和Sal I双酶切后得到预期片段。PacI酶切得到30 Kb大片段和4.5 Kb小片段。转染AD293细胞后收集病毒,经PCR鉴定,获得理想的目的片段。取病毒上清反复感染AD293细胞以扩增病毒,最后所得病毒滴度为2.5×109pfu/ml。结论:成功构建了携带脂肪储存小滴蛋白5基因的重组腺病毒载体,为进一步研究LSDP5基因功能奠定基础。