不同方法从大豆不同组织中提取基因组DNA效果的比较

从大豆组织中获得高质量和足够产量的基因组DNA,是进行大豆分子生物学研究的基础.为进行大豆基因组的PCR,RAPD,SSR等分子生物学研究,分别以大豆种子和其叶片为实验材料,采用改良的SDS法和CTAB法对大豆基因组DNA进行了提取.对DNA的提取效果,采用紫外分光光度检测、琼脂糖凝胶电泳分析及DNA的限制性内切酶图谱分析进行了综合比较.结果表明,在以叶片为材料时,SDS法和CTAB法的大豆基因组DNA的提取效果差别不大,SDS法稍好于CTAB法.在以大豆种子为材料时,SDS法的提取效果明显优于CTAB法,SDS法可从大豆种子中提取到能够充分满足各种分子操作的高质量和数量的大豆基因组DNA.     

一种高质量的红毛丹基因组DNA提取方法

为了提取高质量的红毛丹基因组DNA，本研究以红毛丹叶片为试材，比较改良CTAB法、改良SDS法和试剂盒法对红毛丹叶片DNA的提取效果。结果表明：3种方法均可从红毛丹叶片中提取DNA，但由于改良CTAB法通过多次洗涤，并联合使用PVP和β-巯基乙醇处理，可有效去除红毛丹叶片中的多糖、多酚和蛋白质等物质，所获得的DNA纯度高且完整性较好，可用于SRAP-PCR等分子标记分析。此结果为后续分子生物学等相关研究奠定了基础。     

改良CTAB法用于提取红麻成熟叶片高质量DNA的研究

红麻处于光合高峰期的成熟叶片中的次生物质含量很高,给DNA的提取造成很大的困难。CTAB法能有效去除多糖杂质,但普通CTAB法用于红麻的DNA提取效果很不理想,为使CTAB法能更好地用于红麻的DNA提取,我们对此方法进行了改进,通过前处理除去大部分的杂质,减小了后续操作的难度。为了验证前处理是否会损失DNA,研究了液氮研磨对材料细胞的破碎程度问题,还讨论了DNA提取中的其它一些相关问题。     

改良CTAB法用于提取红麻成熟叶片高质量DNA的研究

红麻处于光合高峰期的成熟叶片中的次生物质含量很高,给DNA的提取造成很大的困难.CTAB法能有效去除多糖杂质,但普通CTAB法用于红麻的DNA提取效果很不理想,为使CTAB法能更好地用于红麻的DNA提取,我们对此方法进行了改进,通过前处理除去大部分的杂质,减小了后续操作的难度.为了验证前处理是否会损失DNA,研究了液氮研磨对材料细胞的破碎程度问题,还讨论了DNA提取中的其它一些相关问题.     

大麻基因组DNA提取方法的比较与优化

以大麻的幼嫩叶片和风干叶片为材料,分别采用优化的SDS法、CTAB法、高盐低pH法和碱裂解法这4种不同方法提取基因组DNA,并比较提取质量和效率.结果表明,采用4种提取方法,大麻干样叶和鲜样叶均可获得清晰DNA目的条带,鲜样叶基因组DNA纯度和得率的顺序为：SDS法＞CTAB法＞高盐低pH法＞碱裂解法,干样叶基因组DNA纯度和得率的顺序为：高盐低pH法＞SDS法＞CTAB法＞碱裂解法,优化的SDS法适用于大麻鲜样叶基因组DNA提取,而大麻干样叶基因组DNA的提取选用优化的高盐低pH法最适宜.     

改良CTAB法提取柚总DNA及叶片保存方法的研究

采用改良的CTAB方法提取龙柚新鲜叶片的总DNA，在提取过程中，采用不同的处理液进行预处理，提得的DNA产量高，纯度好，降解少，可用于PCR扩增，能满足相关的分子生物学研究要求。同时，尝试用饱和NaCl-CTAB保存液来保存新鲜叶片，并对分别保存7天、14天、21天、28天的叶片进行总DNA提取，实验结果表明：保存7天的叶片总DNA提取效果最佳。     

改良CTAB法和高盐低pH值法提取花生DNA的效果

采用改良CTAB法和高盐低pH法提取花生总DNA,结果表明,高盐低pH法提取的花生DNA分子量略小,DNA有一定程度的降解,但得率大大高于CTAB法,按我们稍有改动的实验方法,每克鲜重的叶片,可提取1000μg以上的DNA。两种方法提取的DNA均可酶切完全,RAPD-PCR扩增,结果相同。高盐低pH值法廉价、步骤少、易掌握,是提取花生DNA较好的方法。     

快速大量提取甜菜DNA的新方法

以甜菜幼嫩叶片为材料,通过冷冻真空干燥将材料变成干粉,利用CTAB法对DNA提取程序进行了研究,建立了一种简单、快速的甜菜DNA提取程序,既节省时间,又可获得高质量的DNA,可以满足SSR及SRAP扩增的需要。     

几种常见方法提取番荔枝基因组DNA的比较

以番荔枝幼嫩叶片为材料,分别采用改良高盐低pH值法、改良的CTAB法、SDS法三种方法提取总DNA,通过紫外分光光度法和琼脂糖凝胶电泳法对三种提取方法进行综合比较。结果显示改良的CTAB法所得的DNA纯度和得率较高,SDS法最差。     

茶树不同组织提取DNA质量差异比较

本研究以肉桂品种为材料,采用CTAB法对四个不同组织提取的DNA进行比较,结果显示:叶片中能够得到质量较好且较纯净的DNA;茶籽中提取的DNA浓度最大,但是含有大量RNA和蛋白质等杂质;花蕾和花中得到的DNA不是量非常少就是降解严重,也含有RNA。     

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.     

Mineral composition of some traditional Mexican teas

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots ofTagetes lucida, T. filifolia, Elytraria imbricata, andHolodiscus dumosus, and from root xylem ofCeanothus depressus andPhaseolus ritensis. Native uses of these teas are also described.     

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.