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.     

花生不同部位对提取DNA的影响

采用CTAB法和SDS法，分别从花生的根尖、下胚轴、种子、幼叶中提取基因组DNA，所提DNA片段长度都在21 kb以上；同种方法中部位之间的DNA纯度没有差异，产率差异极其显著，从种子、根尖、下胚轴到幼叶产率依次升高，CTAB法中产率从128．5～498．5ng／mg，SDS法中产率从225．O～542．6ng／mg；两种方法中，相同部位之间只有叶片在纯度上差异显著，产率上相同部位之间的差异极其显著。用CTAB法从叶片中提取DNA，采用RAPD方法，对19个花生品种的基因组进行扩增，结果显示所提DNA满足分子分析的要求。RAPD可用于亲本和品种的鉴定。     

不同方法对甜菜不同组织中总DNA的提取效果

以甜菜的幼嫩叶片、幼嫩花序、萌动种子及糖分积累期块根为提取材料,分别采用高盐低p H法、改良十二烷基硫酸钠(SDS)法、改良十六烷基三乙基溴化铵(CTAB)法及碱裂解法4种不同方法进行总DNA提取,对比不同提取方法及提取部位对提取效果的影响。结果表明,CTAB法适宜于叶片的DNA提取;SDS法适于对花的提取,而且对根和种子的提取效果也优于其它3种方法 ;碱裂解法具有简便快速的优点,但得率低,杂质去除不彻底,有可能影响后续试验,适用于对产量与质量要求不高时的快速提取;高盐低p H法提取的DNA浓度及得率均较低,且产物纯度不高,不建议作为首选方法。甜菜4种组织中,叶片最适合作为提取材料,花次之;根和种子的提取难度较大,建议提取时增加纯化与浓缩步骤。     

大豆叶片DNA提取方法的比较研究

以大豆叶片为材料,对大豆基因组DNA提取方法中若干影响因子如提取液、提取液的浓度、蛋白质去除次数、提取步骤等进行比较研究,试图寻找大豆叶片DNA提取的最佳方法.结果表明,碱裂解法提取速度快,但提取的DNA量少,在SSR分析中,银染效果较CTAB、SDS提取液差,CTAB、SDS提取液均能得到较高质量的DNA;在1%～4%CTAB、SDS提取液浓度下,4%CTAB易使DNA产生降解,但不同浓度提取液提取DNA均可用于SSR分析;提取叶片重量在一定范围内时,随抽提次数减少,DNA浓度增加,纯度下降,但即使用氯仿/异戊醇抽提一次,也能够满足SSR分析的需要;不同提取步骤下,使用氯仿/异戊醇抽提2次后使DNA沉出后再溶解抽提2次和直接抽体4次相比,A260/A280值偏大,但A260/A230值较好.     

SDS法提取石斛基因组DNA的研究

以密花石斛(Dendrobium densiflorum Lindley ex Wallich)为研究试材,对植物SDS方法提取基因组DNA中的若干影响因子诸如药品、试剂配制方法、DNA取材部位、蛋白质去除次数、DNA析出时间、提取样品水浴时间等进行了比较分析。结果表明：不同的SDS缓冲液配制方法提取效果差异较大,Wang's配方产率及纯度都较高;石斛花苞的DNA提取产率较叶片高,但纯度较叶片低;提取过程中,适宜的水浴时间当为30～40 min,过短DNA产率下降,过长会引起DNA的降解,或最后产物中增加     

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。     

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.     

大豆种子DNA的提取方法

用大豆干种子和叶片分别为材料，进行以PCR为目的大豆模板DNA的提取和分析。实验结果表明：利用大豆干种子为材料，虽然在提取DNA量上比用叶片提取的少，但对PCR扩增结果没有影响。因此，用大豆干种子直接提取DNA可以节省育苗时间，获得完全可以满足试验要求的大豆模板DNA。     

不同方法对甜菜叶片基因组DNA提取效果比较与适用性探讨

对比了7种不同原理的提取方法对甜菜叶片基因组DNA的提取效果,从得率、纯度、耗时等多方面分析DNA提取效果,为不同研究目的确定了最适的提取方法。最终确定了SDS法是最适合自甜菜叶片中低成本大量提取DNA的方法,CTAB也基本能满足要求,吸附柱法是最适合高通量提取优质DNA的方法,碱裂解法是最适合样品迅速检测的方法,必要时可改用ROSE法。柠檬酸钠法产物质量不高且操作不够简便,尿素法产物纯度过低且耗时过长,在应用上未见优势。     

改良高盐高pH法提取大豆DNA

大豆除了含有大量的脂类和蛋白质外,还含有糖类和酚类物质,为解决难于从大豆中提取高质量DNA和传统提取方法耗时长的问题,本研究以中豆41与天隆一号的幼嫩叶片(V3)和成熟种子作为材料,对高盐低pH法进行改良,提高其裂解液pH值,同时结合冷冻裂解法缩短裂解时间,使用不同pH值醋酸钠纯化DNA,并与经典CTAB法进行比较,评价其提取DNA的效果及其应用范围。结果表明,高盐高pH法对成熟种子的DNA提取效率较高,且蛋白与RNA污染少。CTAB法提取的DNA虽然完整性较高,但是耗时较长,蛋白与RNA污染较多。另外,高盐高pH法提取的DNA PCR扩增条带清晰,与常规CTAB法提取DNA扩增效果一致,但其DNA质量不能满足高通量测序要求。综上,改良的高盐高pH法是一种快速有效的大豆DNA提取方法,可满足常规分子试验的要求。     

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).