根癌农杆菌介导的大豆子叶节转化体系的优化

以13种不同基因型的大豆为材料,研究了大豆外植体再生过程中不同大豆基因型对丛生芽数目的影响,选取优势基因型为受体材料,比较了在草丁膦和潮霉素筛选压力下外植体的再生情况,并确定其合适的筛选浓度,在对农杆菌介导的子叶节转化体系优化的基础上进行了大豆转化效率的研究。结果显示:在相同的芽诱导条件下,山宁14产生的丛生芽最多,更适合于大豆子叶节转化;与其它筛选剂相比,采用潮霉素的梯度筛选更有利于抗性苗的成活,其最适筛选浓度为8 mg.L-1;通过检测GUS基因的表达和分子鉴定证明外源的GUS基因已插入到转基因植株的基因组中,转化效率达到3.2%。     

几丁质酶基因转化甜菜的初步研究

本试验通过农杆菌（Ａｇｒｏｂａｃｔｅｒｉｕｍ）介导法将菜豆几丁质酶基因导入甜菜（Ｂｅｔａ ｖｕｌｇａｒｉｓ,Ｌ．）,再生植株经卡那霉素筛选后,进行ＰＣＲ分析,结果表明：再生植株的转化率为２７．３％,甜菜叶柄是转化的较好受体。     

以cosmid质粒为载体的稻瘟病菌转化体系的建立及病菌基因文库的构建

用潮霉素Ｂ（ｈｙｇｒｏｍｙｃｉｎＢ）抗性基因和λ噬菌体的ｃｏｓ位点组建了一种ｃｏｓｍｉｄ质粒ｐＳＶｈｙｇＢ，以此质粒建立了稻瘟病菌的转化体系，并且构建了病菌的基因组文库。结果表明，ｐＳＶｈｙｇＢ质粒可用于稳定地转化稻瘟病菌，转化频率约为１５个转化子／μｇＤＮＡ，电击法转化并不能有效地提高稻瘟病菌的转化频率。构建的稻瘟病基因文库中包含将近１００００个重组子克隆，随机挑取１２个重组子的鉴定表明，都包含有外源插入片段，说明所建文库已达要求。     

重组人血清白蛋白在紫花苜蓿中的转基因表达

为获得高产重组人血清白蛋白的转基因紫花苜蓿"游客"(Medicago sativa L. cv.‘Eureka’)株系用于规模化生产rHSA,构建了rHSA植物表达载体。以紫花苜蓿子叶愈伤组织为受体,通过农杆菌介导法进行遗传转化,筛选出潮霉素抗性植株,提取抗性再生紫花苜蓿植株基因组DNA做PCR鉴定,结果表明重组人血清白蛋白基因片段已整合到紫花苜蓿基因组中;提取转基因植株总蛋白,Western blotting检测结果表明rHSA在转基因植株中成功表达。此结果表明转基因紫花苜蓿可稳定表达rHSA。      

八氢番茄红素合成酶基因(PSY)对大豆的遗传转化

以三个大豆品种的无菌苗子叶节为受体,以PSY为目的基因,应用根癌农杆菌介导法对大豆进行了遗传转化,经子叶节丛生芽诱导、茎伸长培养、生根培养和潮霉素选择培养,获得了完整的抗性再生苗,经PCR和PCR-Southern分析鉴定,初步证明外源基因PSY已整合到大豆的基因组中,并对影响遗传转化的因子进行了研究.     

农杆菌介导的芒果胶孢炭疽菌遗传转化及致病性缺陷突变体的筛选

构建含潮霉素抗性基因和GFP基因的双元载体pCAMBgfp,以其为转化载体用农杆菌EHA105介导的方法对芒果胶孢炭疽菌Cg-8菌株进行遗传转化,以潮霉素抗性和GFP荧光来筛选阳性转化子。然后,通过离体接种芒果叶片和果实观察病斑大小筛选致病性缺陷转化子。结果获得500个阳性转化子,转化效率为平均106个孢子可获得400个左右同时具有潮霉素抗性和GFP荧光的阳性转化子,且其经多次在无潮霉素的培养基上传代后能得到稳定遗传。随机挑选其中13个突变体进行PCR检测,均可扩增出潮霉素基因目的条带,致病性分析从中筛选得到8个致病性减弱或缺失突变体。     

小麦遗传转化中潮霉素筛选体系的建立及应用

为建立小麦遗传转化中高效的潮霉素筛选体系,以小麦品种郑麦9023的幼胚愈伤组织为材料,探讨了潮霉素浓度、处理时间、恢复培养与否对愈伤组织分化和再生的影响,并对基因枪转化的郑麦9023、邯6172、龙麦30、龙麦31的愈伤组织进行了筛选。结果表明,对小麦幼胚愈伤组织基因枪遗传转化后的筛选以50mg·L-1潮霉素处理30d为宜;恢复培养不能提高筛选阶段愈伤组织的存活率和分化率,但能提高转化后期的成苗率。经过筛选发现郑麦9023抗性愈伤和T0代抗性植株根系及花器官中均有GUS基因的表达;4个小麦品种抗性植株中潮霉素磷酸转移酶基因(hpt)和候选基因PCR阳性率分别为78.95%和73.68%以上;龙麦30、龙麦31的T1代植株的候选基因PCR阳性率分别在33.33%和73.33%以上,T2代阳性率分别在71.43%和75.00%以上。     

农杆菌介导的DnMADS2基因转化金钗石斛初步研究

为建立稳定有效的金钗石斛转化体系,进一步研究花发育相关基因的功能,为石斛兰分子育种提供基础,本研究以金钗石斛类原球茎（PLBs）为转化受体,通过农杆菌介导的方法将DnMADS2基因转入金钗石斛。结果表明：用20 mg/L潮霉素筛选4个月后获得抗性PLBs,对其进行HPT基因和DnMADS2基因的PCR检测表明,目的基因已成功整合到PLBs中。获得的转化PLBs在抗性培养基上分化为不定芽后,再经生根壮苗培养获得转化植株。对转化植株进行Southern检测,结果表明,DnMADS2基因已整合到5株金钗石斛转化植株基因组中。据此建立的稳定高效的金钗石斛转化体系和获得的转基因植株,将为DnMADS2基因功能的进一步研究和金钗石斛转基因育种奠定基础。     

香蕉ACC合成酶含3''''末端的cDNA克隆

采用 ３＇ＲＡＣＥ方法对香蕉（Ｍｕｓａ ＡＡＡ Ｃａｖｅｎｄｉｓｈ Ｓｕｂｇｒｏｕｐ）ＡＣＣ合成酸含 ３＇末端的 ｃＤＮＡ进行扩增，扩增产物被克隆到ｐＣＲ■２．１载体上，转化大肠杆菌ＤＨ５ α，筛选到重组质粒（ｐＡＣＳ２），并对插入片段进行序列测定。结果表明，３＇ＲＡＣＥ产物长 １６８０ ｂｐ，其中一个 开放读框内的核苷酸序列编码４４４个氨基酸，氨基酸序列包括了ＡＣＣ合成酶中所应具有的７个高度保守区。同时该产物还有长２６９ ｂｐ的３＇末端，并具有完整的 Ｐｏｌｙ（Ａ）尾（２４ｍｅｒ）。     

水稻花器介导法转目标基因的研究

研究和分析了受体品种、质粒浓度对水稻花器介导法转化的影响。供试的20个水稻品种（系）中有9个适用于质粒转化,不同受体品种要求的质粒适宜浓度不同。经潮霉素（hygromycin）筛选、PCR分析、抗稻纹枯病和稻瘟病鉴定、GUS活性检测转基因水稻后代,验证了水稻花器介导法转目标基因的有效性。获得了含细菌几丁质酶基因的优丰162转基因T4 代,它表现出对叶瘟病和纹枯病抗性有明显提高。     

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).