不同方法提取棉花DNA的比较

主要通过选用国丰棉12为材料,对不同方法提取出的DNA进行扩增,然后进行琼脂糖凝胶电泳分析,结果表明:改良SDS法和改良CTAB法分别优于原SDS法和CTAB法,原SDS法和CTAB法分别优于氯仿一异戊醇法,由改进方法提取的棉花基因组DNA质量较高,能满足SSR等后续分子生物学研究的需要.     

小麦TILLING突变体检测中基因组DNA提取方法的优化

为了优化小麦高通量TILLING突变体扫描所需基因组DNA提取的方法,对利用SDS法、改良SDS法、CTAB法、改良CTAB法、AxyPrep DNA提取试剂盒、Qiagen DNeasy Plant Mini Kit试剂盒以及再生Qiagen硅胶柱方法提取的小麦基因组DNA进行了系统比较。结果表明,尽管7种方法所提取DNA的纯度及琼脂糖凝胶电泳检测结果均良好,但再生Qiagen硅胶柱方法、CTAB法和改良SDS法的DNA浓度显著高于其他方法。根据小麦细胞分裂素氧化酶基因1(TaCKX1)的DNA序列设计引物,以新鲜DNA样品用于PCR扩增大于1 000bp的片段时,后4种方法扩增效果优于前3种方法;DNA在-20℃下保存100d后重新进行PCR扩增时,则只有Qiagen试剂盒和再生Qiagen硅胶柱2种方法提取的DNA能扩增出大于1 000bp的片段。采用本实验室与新西兰坎特伯雷大学合作建立的再生硅胶柱与自配提取液提取小麦基因组DNA,既保证了DNA的高质量,又降低了使用试剂盒的成本,为小麦TILLING库的构建及其他相关试验提供了一种经济有效的DNA提取方法。     

甜菜基因组DNA三种提取方法的对比研究

采用CTAB法、SDS法、蛋白酶K法分别提取甜菜基因组DNA,并对得到的DNA进行含量测定、PCR扩增效果鉴定、限制性内切酶酶切。比较3种方法的提取效果,结果表明:CTAB法提取的DNA产量最高,蛋白质和多糖含量低,PCR结果和酶切结果均比较好;SDS法提取的DNA产量也较高,PCR结果不如CTAB法效果好;蛋白酶K法提取的DNA产量最低,且含有较多的RNA,PCR扩增无结果。所以,CTAB法是适合于甜菜基因组DNA提取的最佳方法。     

橡胶林土壤微生物2种DNA提取方法的比较

比较了橡胶林土壤微生物CTAB-SDS提取法和SDS提取法的效果。结果表明,2种提取方法均获得约 23.1kb的DNA片段,2种提取方法在颜色、提取量和纯度上存在较大差异。CTAB-SDS提取法提取DNA的纯度较好,不需要纯化可以直接用于PCR扩增、酶切等后续操作;SDS提取法提取的纯度低,不能直接用于PCR扩增。2种方法都适合橡胶林土壤DNA的提取,如果要求获得纯度高的DNA,CTAB-SDS提取法是最佳选择。橡胶林土壤微生物DNA的提取,推荐使用CTAB-SDS提取法。     

两种不同甘蔗基因组DNA提取方法的比较

采用改良CTAB法和SDS法提取甘蔗嫩叶与正一叶基因组DNA,通过琼脂糖凝胶电泳与紫外光吸收检测,证明SDS法能获得高质量的DNA,适合分子生物学操作的要求,为后续甘蔗遗传多样性分析、遗传图谱构建等研究奠定基础。     

彩色甜椒基因组DNA提取方法的优化

以不同颜色的甜椒为试验材料，采用CTAB法、SDS法、ROSE法和氯化苄法提取彩色甜椒基因组DNA。结果表明，CTAB法所提取DNA的质量和纯度较高，以此DNA为模板进行RAPD-PCR分析，DNA扩增效果较好，带形清晰、整齐，说明CTAB法提取的DNA较为完整，能用作RAPD-PCR模板来开展彩色甜椒分子水平的研究。     

玉米丝黑穗病菌DNA提取及UP-PCR反应体系建立

采用CTAB法、SDS法和尿素法,从玉米丝黑穗病菌液体培养物中提取基因组DNA,比较其提取效果。结果表明：改进的CTAB法可有效去除多酚、多糖和色素等杂质对DNA的污染,可获得高质量模板DNA。以此为模板进行UP-PCR(Universally Primed PCR)反应,对UP-PCR扩增反应中的一些重要参数进行了优化,建立适合于玉米丝黑穗菌的UP-PCR反应体系。     

冠状散囊菌基因组DNA提取方法比较研究

为快速、简单、有效的获得冠状散囊菌DNA,分别使用溶菌酶破壁法、纤维素酶破壁法、果胶酶破壁法、CTAB法、SDS法提取冠状散囊菌菌丝体和子囊孢子的基因组DNA,然后进行琼脂糖凝胶电泳、ITS序列的PCR扩增检测以及紫外分光光度计测定DNA浓度和纯度。实验结果表明：5种方法均能提取出冠状散囊菌基因组DNA,酶法中溶菌酶最...     

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。     

一种优化的提取花生根尖细胞DNA的方法

采用传统的CTAB法和SDS法提取花生根尖细胞的DNA,SDS法提取效果优于CTAB法,但仍不能满足实验要求。对传统的SDS法进行简化和优化,建立了改良SDS法,利用改良SDS法提取花生根尖DNA,效果较好,能够满足分子生物学研究需要。     

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.     

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.     

Evolutionary aspects of the trade-off between seed size and number in crops

Whereas the concept that availability of resources drives seed production is sound in principle, it is incomplete as there are many solutions to the allocation of resources that derive from the trade-off between number and size. This paper examines evolutionary aspects of this trade-off in annual grain crops. The analysis is centred on the working hypotheses that, for a given species and environment, allocation of resources to reproduction involves (H1) high plasticity in seed number, which allows for variable resource availability, and (H2) a relatively narrow range of seed size that results from evolutionary and agronomic selection. Comparisons between crops and fish are used to highlight common evolutionary elements in taxa where parents provide little or no care to their offspring, with the consequence that both number and early survival of offspring, hence fitness of parents, are partially related to embryo size and reserves.

The plasticity of seed number in relation to availability of resources is analysed against the established relationship between offspring number and parent growth rate during critical stages. The notion that seed size is under stabilising selection is analysed against three conditions: (1) mean seed size is conservative for a given species and environment, (2) seed size affects fitness, and (3) seed size is heritable. Databases from published papers were compiled to analyse the relative variability of seed size and number, and the heritability of seed size. Evidence for and against the link between seed size and parental fitness is revised using the Smith–Fretwell model as framework (Am. Nat., 108, 499–506).

The proposal of high plasticity of seed number and narrow variability of seed size resulting from stabilising natural selection is generally consistent with evolutionary and genetic considerations. Agronomic selection may have reinforced natural selection leading to relatively narrow seed size in species such as wheat and soybean, where cultivated types retained high plasticity for seed number. In contrast, selection for one or few inflorescences in crops like sunflower and maize may have morphologically reduced seed number plasticity and increased variability of seed size and its responsiveness to resource availability in relation to their wild ancestors.     

Citrus Flavonoids in Fruit and Traditional Chinese Medicinal Food Ingredients in China

Flavonoids-enriched tissues of citrus such as peel, immature fruit and flower are consumed as culinary seasonings, tea ingredients in China for centuries. This HPLC quantitative study on the five citrus flavonoids, naringin, hesperidin, neohesperidin, sinensetin and nobiletin on a wide range of Chinese citrus fruits and several Traditional Chinese Medicinal food ingredients in East China, revealed a great diversity in flavonoid composition. Huyou peel (C. paradisi cv. Changshanhuyou) was found to be the best naringin (3.25%) and neohesperidin (2.76%) source; C. aurantium, a major ingredient of several citrus-related TCM, is also a suitable source of naringin and neohesperidin, and a good juice source for flavanone glycosides; the peel of Wenzhoumiju (C. unshiu) is one of the richest local species in hesperidin (up to 6.25%); Zaoju (C. subcompressa) has the highest content of nobiletin (0.59%), a polymethoxylated flavone. LC-ES-MS analysis of Zanthoxylum genus for flavonoids revealed for the first time the presence of significant amounts (0.74%) of hesperidin in the root of Liangmianzhen (Z. nitidum (Roxb.) DC), a relative of Sichuan pepper, which is a spice widely used in China.     

Effect of a continuous hot water treatment of potato tubers on seed-borne fungal pathogens

Summary The viability of five pathogens was decreased by treatment with hot water when tested in vitro.Polyscytalum pustulans was most sensitive andRhizoctonia solani least sensitive. Potato tubers were exposed to 55°C for 5 min in a commercial continuous hot water treatment plant using naturally contaminated seed tubers and tubers which had been inoculated by dipping in comminuted cultures. The frequency of eyes colonised byP. pustulans, Helminthosporium solani, andR. solani was reduced to virtually zero and the effect persisted on tubers subsequently stored at 4°C and at 15°C for up to 16 wk. Results withColletotrichum coccodes were inconclusive. Treatment suppressedPenicillium spp. which, however, rapidly recolonised the eyes during storage, leading to higher contamination levels in the treated than in the untreated tubers. With tubers inoculated withPhoma foveata, good control was achieved when the incubation period before treatment was 10 d but not when the period was 42 d.     

Role of Benzoxazinones in Cereals

Summary

Heterocyclic 1,4-benzoxazin-3-ones and related benzox-azolinones are important natural products of the cereal crops maize, wheat and rye. Much research has focused on the role of these compounds as defensive agents against plant diseases and pests. Studies of a wide variety of biological effects on herbivores and nematodes, plant pathogenic fungi and bacteria are reviewed in this article. Phytotoxic activity of the compounds is also considered with respect to allelopathic interaction with higher plants. Recent investigations of molecular aspects of interactions of cyclic hydroxamic acids and related benzoxazo-linones with acceptor organisms have demonstrated different effective detoxification strategies and tolerance mechanisms. This research has greatly advanced our knowledge about the multiple roles that these allelochemicals play in ecological systems.     

Potential of dry fractionation of wheat bran for the development of food ingredients,part I: Influence of ultra-fine grinding

Wheat bran is an undervalued by-product of white flour and has great nutritional potential due to its high content in fibres and bioactive compounds. Micronized bran could be used as a food ingredient to improve the nutritional potential of cereal products, or be used as a starting material for other processes (bioactive compound extraction or bran fractionation). The aim of this work was to find a way to efficiently decrease the particle size of bran. The influence of the grinding temperature (ambient or cryogenic grinding) on the granulometric distribution of particles, their composition, and their microstructure was studied, at lab-scale and pilot-scale. It showed that the intrinsic characteristics of bran (glass transition within intermediate layers at −46 °C) had more influence on its grinding behaviour than the type of grinding device used: the particles size distributions obtained after grinding at lab-scale and pilot-scale were very similar. At both scales, the granulometric curves were narrow for cryogenic grinding, while for ambient grinding they were spread over the whole particle size range. Ultrafine particles were obtained in both ambient and cryogenic conditions. Negative temperatures, by increasing the material’s brittleness, favoured a fast fragmentation of bran: one step of cryogenic grinding allowed a median particle size of nearly 50 μm to be reached, whereas three successive steps of ambient grinding were needed for the same result. On the other hand, ambient temperature favoured the dissociation of the different constituent layers of wheat bran, and produced less composite particles than cryogenic grinding.     

Multiple use of plants: Studies on selenium incorporation in some agricultural species for the production of organic selenium compounds

The technique of spraying plants with inorganic forms of selenium can be employed for phytochemical production of organic selenium compounds. Fractionation of the plant material makes it possible to produce a highly concentrated and well defined selenium supplement with potential use in animal and human nutrition. The fractionation also gives opportunities to combine production of organic selenium compounds with other products, for example plant fibres. Multiple use of plants can contribute to a more efficient utilization of land area (in comparison to monocultures solely adapted to food production). It also gives the opportunity to develop systems suitable for long term fixation of carbon, as long as the plant material is not reoxidised to carbon dioxide. Plant fibres could provide raw material for the production of paper or building materials in combination with the production of organic selenium compounds preferentially accumulated in another fraction of the processed plant.     

Biological factors influencing the transmission of potato leafroll virus by different aphid species

Summary Macrosiphum euphorbiae, collected in the field from potato plants infected with potato leafroll virus (PLRV), transmitted the virus to fewer potato plants in a field trial than did laboratory-rearedMyzus persicae. In the laboratory,M. persicae was the only efficient vector of PLRV fromPhysalis floridana seedlings, potato sprouts or excised leaves toP. floridana. Two clones ofM. euphorbiae and one clone ofAulacorthum solani transmitted PLRV from infected potato plants toNicotiana clevelandii as effeciently asM. persicae but a clone ofAphis gossypii was an inefficient PLRV vector. An isolate of PLRV, whichM. persicae transmitted inefficiently from potato toN. clevelandii, was also transmitted inefficiently byM. euphorbiae andA. solani.