聚乙二醇包覆的维生素C脂质体的制备及性质研究

利用聚乙二醇(PEG)包覆脂质体以提高脂质体的稳定性.先用薄膜分散-超声乳化法制备维生素C脂质体,然后将PEG溶液与维生素C脂质体混合制备PEG包覆的脂质体.电镜照片证明PEG在脂质体外形成了一层膜,粒径增加.脂质体经PEG包覆后包封率增加.稳定性试验测定不同温度下脂质体吸光度变化及脂质体中丙二醛含量变化情况,得到较佳贮存条件为4℃避光,PEG包覆后的脂质体吸光度与丙二醛含量增大幅度均较小.结果表明:用PEG可有效包覆维生素C脂质体并提高脂质体的稳定性.     

大豆磷脂脂质体的制备

以3种不同的大豆磷脂为材料,用反相蒸发法制备脂质体,通过对其形态、粒径、包封率、泄漏率和稳定性的测定,研究大豆磷脂组成对脂质体性质的影响.结果表明,脂质体为圆球状的小囊泡,以含有磷脂酰胆碱（PC）93.62%的磷脂SPC-3为材料制备的脂质体相比较于以PC含量分别为31.29%和58.19%的磷脂SPC-1和SPC-2制备的脂质体,具有最大的包封率、粒径和最小的泄漏率.稳定性研究结果表明以磷脂SPC-1为材料制备的脂质体稳定性好.     

亚麻酸脂质体的制备工艺及质量标准研究

目的优选亚麻酸脂质体的制备工艺同时对其质量进行评价与分析。方法采用注入法制备亚麻酸脂质体,以包封率为指标优选最佳的脂质体制备工艺。结果在乙醇加入量8ml,加热温度55℃,磷酸盐缓冲液p H值为7.5的条件下,月见草油(紫苏油)与大豆软磷脂按照1:1混合后其包封率达到最高值。结论采用脂质体制备的亚麻酸工艺稳定、质量可靠。     

斜叶黄檀精油脂质体的制备及其抑制黑色素合成的研究

研究不同浓度斜叶黄檀精油（0、5、10、15、20 mg/L）对制备的脂质体稳定性及其抑制斑马鱼胚胎黑色素合成的影响。通过粒径、多分散系数、Zeta电位、包封率指标来表征斜叶黄檀精油脂质体,评价其在4 ℃下储藏4周的稳定性。结果发现,10 mg/L的斜叶黄檀精油脂质体在储藏过程中最为稳定,包封率达到最大,为45.10%±0.27%。斜叶黄檀精油脂质体可呈浓度依赖式的降低斑马鱼胚胎的酪氨酸酶活性和黑色素含量;20 mg/L的斜叶黄檀精油脂质体对斑马鱼胚胎的酪氨酸酶活性和黑色素含量的抑制作用与30 mg/L的斜叶黄檀精油的效果无显著差异。本研究构建了相对稳定的斜叶黄檀精油脂质体载体,研究了斜叶黄檀精油脂质体的褪黑效果,为斜叶黄檀精油脂质体作为皮肤增白剂的开发和利用提供了理论基础。     

海藻酸钠/壳聚糖基橡胶树死皮康复营养剂微胶囊的制备工艺优化

橡胶树死皮已成为制约天然橡胶生产发展的重要因子之一,研发轻简、高效的死皮防治技术是目前生产中亟需解决的问题。本文以海藻酸钠/壳聚糖为壁材,橡胶树死皮康复营养剂主要有效成分为芯材,通过复凝聚反应将橡胶树死皮康复营养剂制备成微胶囊。以微胶囊的包封率、载药量为制备工艺优化指标,通过L₁₆(4 ⁵)正交实验得出微胶囊的最佳制备工艺条件。研究结果表明,当壳聚糖浓度为2.0 mg/mL、营养剂用量为1 g,体系反应温度为40 ℃,pH为5,10%戊二醛用量为30 mL时,该工艺条件下制备的微胶囊相对圆整、粒度分布相对均匀（10~40 μm）,其包封率达69.31%、载药量达14.35%。所得的最佳工艺制备条件为后期实现木质部埋植橡胶树死皮康复营养剂缓释微胶囊打下良好基础;为最终实现新型高效的橡胶树死皮康复技术应用提供依据。     

维生素E、维生素C和BHT对大豆磷脂脂质体的抗氧化作用

用共轭二烯法和硫代巴比妥酸法,研究了维生素E对大豆磷脂脂质体的抗氧化作用,以及维生素C和BHT对维生素E抗氧化作用的影响．结果表明,维生素E可抑制大豆磷脂脂质体的氧化,其抑制作用随着加入量的增加而增强。维生素C和BHT对维生素E的抗氧化作用具有明显的协同作用,BHT的协同作用强于维生素C。因此以大豆磷脂为原料制备脂质体的最佳抗氧化剂是维生素E和BHT,最佳用量是x（维生素E）=5％,x（BHT）=4％。     

脂质体用大豆卵磷脂的制备及质量评价

以大豆磷脂为原料,用溶剂-超临界CO2萃取法制备脂质体用高纯度大豆卵磷脂,并对其质量进行评价.结果表明大豆卵磷脂的含量是94.98%,丙酮不溶物的含量是99.0%,酸值是20.6KOH mg/g,干燥失重是0.63%,己烷不溶物的含量0.18%,砷盐的含量是2.1×10-6 %,重金属的含量是2.0×10-5 %.以精制的大豆磷脂为原料制备的脂质体,在透射电镜下呈圆球状.粒径为164 nm,Zeta电位为-28.50 mv,包封率是32.43%.     

固态发酵大豆制备的抗氧化肽的活性分析

综合评价用固态发酵法制备的大豆抗氧化肽的抗氧化活性.通过T-AOC方法测定总抗氧化能力、通过水杨酸法测定·OH、通过邻苯三酚法测定O2ˉ、通过卵磷脂法测定脂质体过氧化、通过POV值法测定抗油脂自氧化.大豆抗氧化肽的总抗氧化能力为50.07 U、对羟基自由基的清除率达到85.68%、抑制邻苯三酚自氧化能力达到23.61 U/mL、抑制脂质体过氧化率为34.58%、对油脂过氧化抑制抑制率为30%.用固态发酵法制备出的大豆抗氧化肽具有较强的还原能力、能清除羟基自由基、抑制邻苯三酚自氧化,并能够对脂质体过氧化和油脂过氧化具有一定的清除作用能力.     

抗黄曲霉毒素单克隆抗体F(ab')2片段的制备与活性

为剧毒靶标(黄曲霉毒素)绿色分析提供高效抗体,在已有抗黄曲霉毒素杂交瘤细胞株1Cll的基础上,通过小鼠腹水法制备单克隆抗体,经胃蛋白酶酶解,制备F(ab')2片段,发现在优化条件37C、pH4.1柠檬酸缓冲液中酶解4.5h,可高效制备F(ab')2片段.通过酶联免疫吸附法(ELISA)比较了抗体片段与原始抗体的识别活性,发现F(ab')2片段效价达到1∶320000,是原抗体效价的1.5倍;灵敏度(IC50)为8.7pg/mL,保持了原抗体的抗原结合能力.     

HPLC法测定菠萝果实中8种维生素含量的研究

优化了利用高效液相色谱法测定菠萝果实中脂溶性维生素（VA、VE）和水溶性维生素（VC、 VB3、 VB12、 VB6、 VB2、 VB1）的方法; 脂溶性维生素以甲醇 ∶ 乙酸乙酯（V甲醇 ∶ V乙酸乙酯=95 ∶ 5）溶液为流动相, 流速为1.0 mL/min, 柱温25 ℃, 检测波长275 nm。 水溶性维生素以0.005 mol/mL己烷磺酸钠（pH3.2）∶ 甲醇（V乙烷磺酸钠∶ V甲醇=7∶ 3）为流动相, 流速为1.0 mL/min, 柱温30 ℃,于254 nm处测定吸光值。试验结果表明： 其线性相关系数在0.999 7～1.000 0之间, 线性关系良好。VA、 VE的峰面积RSD分别为1.48％、1.31％;VC、 VB3、 VB12、 VB6、 VB2和VBl的峰面积RSD分别为1.35％、 1.78％、 1.50％、 1.52％、 0.93％和1.10％。VA、 VC、 VB3、 VB6的平均加样回收率分别为94.2％、 102.3％、 91.0％、 95.2％。     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Cyanobacteria Secondary Metabolites as Biotechnological Ingredients in Natural Anti-Aging Cosmetics: Potential to Overcome Hyperpigmentation,Loss of Skin Density and UV Radiation-Deleterious Effects

The loss of density and elasticity, the appearance of wrinkles and hyperpigmentation are among the first noticeable signs of skin aging. Beyond UV radiation and oxidative stress, matrix metalloproteinases (MMPs) assume a preponderant role in the process, since their deregulation results in the degradation of most extracellular matrix components. In this survey, four cyanobacteria strains were explored for their capacity to produce secondary metabolites with biotechnological potential for use in anti-aging formulations. Leptolyngbya boryana LEGE 15486 and Cephalothrix lacustris LEGE 15493 from freshwater ecosystems, and Leptolyngbya cf. ectocarpi LEGE 11479 and Nodosilinea nodulosa LEGE 06104 from marine habitats were sequentially extracted with acetone and water, and extracts were analyzed for their toxicity in cell lines with key roles in the skin context (HaCAT, 3T3L1, and hCMEC). The non-toxic extracts were chemically characterized in terms of proteins, carotenoids, phenols, and chlorophyll a, and their anti-aging potential was explored through their ability to scavenge the physiological free radical superoxide anion radical (O₂^•−), to reduce the activity of the MMPs elastase and hyaluronidase, to inhibit tyrosinase and thus avoid melanin production, and to block UV-B radiation (sun protection factor, SPF). Leptolyngbya species stood out for anti-aging purposes: L. boryana LEGE 15486 presented a remarkable SPF of 19 (at 200 µg/mL), being among the best species regarding O₂^•− scavenging, (IC₅₀ = 99.50 µg/mL) and also being able to inhibit tyrosinase (IC₂₅ = 784 µg/mL), proving to be promising against UV-induced skin-aging; L. ectocarpi LEGE 11479 was more efficient in inhibiting MMPs (hyaluronidase, IC₅₀ = 863 µg/mL; elastase, IC₅₀ = 391 µg/mL), thus being the choice to retard dermal density loss. Principal component analysis (PCA) of the data allowed the grouping of extracts into three groups, according to their chemical composition; the correlation of carotenoids and chlorophyll a with MMPs activity (p < 0.01), O₂^•− scavenging with phenolic compounds (p < 0.01), and phycocyanin and allophycocyanin with SPF, pointing to these compounds in particular as responsible for UV-B blockage. This original survey explores, for the first time, the biotechnological potential of these cyanobacteria strains in the field of skin aging, demonstrating the promising, innovative, and multifactorial nature of these microorganisms.     

Marine Pharmacology in 2009–2011: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis,and Antiviral Activities; Affecting the Immune and Nervous Systems,and other Miscellaneous Mechanisms of Action ?

The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.     

Recent Modifications of Chitosan for Adsorption Applications: A Critical and Systematic Review

Chitosan is considered to be one of the most promising and applicable materials in adsorption applications. The existence of amino and hydroxyl groups in its molecules contributes to many possible adsorption interactions between chitosan and pollutants (dyes, metals, ions, phenols, pharmaceuticals/drugs, pesticides, herbicides, etc.). These functional groups can help in establishing positions for modification. Based on the learning from previously published works in literature, researchers have achieved a modification of chitosan with a number of different functional groups. This work summarizes the published works of the last three years (2012–2014) regarding the modification reactions of chitosans (grafting, cross-linking, etc.) and their application to adsorption of different environmental pollutants (in liquid-phase).