玳玳花瓣脂氢过氧化物裂解酶基因cDNA的克隆及原核表达

以玳玳花瓣为材料,采用RT-PCR和RACE技术,克隆了玳玳HPL基因cDNA全长,全长为1 776 bp,其中包含52 bp的5′非编码区,224 bp的3′非编码区,1 500 bp的编码区(编码499个氨基酸,分子量为55.7 ku)。将该HPL基因cDNA编码区的核苷酸序列及所推导的氨基酸序列与其他植物的HPL基因cDNA序列进行比较,推断玳玳花瓣HPL属于13-HPL类。通过PCR扩增得到了玳玳HPL基因组全长。测序结果显示玳玳HPL基因中包含1个长2 374 bp的内含子。将分离出来的玳玳HPL基因cDNA的编码区序列插入pET-15b载体上构建原核表达载体,在细菌BL21细胞中进行原核表达。结果表明:该编码区片段可在原核细胞中大量表达,其表达产物分子量大小约为55 ku,与13-HPL蛋白的分子量55.7 ku相符。本研究为下一步利用HPL基因cDNA进行遗传转化研究奠定基础,将为花卉香味的遗传改良提供一条新途径。     

小麦抗源材料HPL60469对CY32的抗性遗传分析

分析了HPL60469×辉县红的F2、F2抗病单株自交的F3株系及F1与辉县红的回交后代群体对条中32小种（CY32）的抗性反应,F2群体的抗感分离比例符合3∶1,F3株系中抗性分离和不分离的株系比例符合2∶1;回交后代群体的抗感分离比例符合1∶1。试验证明,HPL60469对条中32小种的抗性由1对显性基因控制的。以HPL60469为母本分别与已知携带抗病基因Yr26的小麦材料92R137、贵农21杂交,获得F1和F2群体。两个F1群体中的所有单株均对条中32小种表现免疫;两个F2群体对条中32小种的抗感分离均符合15∶1。说明HPL60469与92R137和贵农21含有不同的抗病基因,即HPL60469的抗病基因不是Yr26/Yr24。结合HPL60469的系谱分析证明,HPL60469含有1对新的抗CY32的显性基因。     

利用转基因技术初步鉴定香蕉RNA解旋酶基因功能

本研究利用前期抑制差减杂交技术筛选获得的香蕉果实上调表达的基因片段,经NCBI比对,表明该基因片段属于香蕉ATP依赖的RNA解旋酶(Helicase)基因家族成员,含有完整的RNA解旋酶超家族C-末端结构域HELICc结构。经Southern杂交证实,此RNA解旋酶基因在香蕉基因组中只有一个拷贝。构建RNA解旋酶基因的反义基因植物表达载体PBIPC86,转化番茄获得6株转基因番茄植株。转基因番茄植株的叶、花和生长形态均有变异,部分转基因番茄生长势弱。该研究结果对鉴定香蕉RNA解旋酶基因功能奠定了初步基础。     

甘蔗转HC-Pro基因的研究

通过基因枪(PDS-1000He)轰击法将构建好的多功能蛋白HC-Pro的植物表达载体pHCFL与带PMI筛选标记基因的pZMLR14植物表达载体共转化导入易感花叶病甘蔗品种福农95-1702的胚性愈伤组织中,转化的愈伤经甘露糖筛选后获得抗性转化甘蔗幼苗。经PCR检测、氯酚红显色、RT-PCR检测和DNA点杂交分析获得转HC-Pro的转基因植株,转化率为0.8%(HC-Pro基因)、1.7%(PMI基因)和0.4%(HC-Pro基因+PMI基因)。花叶病毒接种实验结果显示,未转基因植株的发病率为75%,而转基因植株均系统性发病,推测由于HC-Pro的大量表达抑制了甘蔗体内自身的RNA沉默机制而使病情加重。其它农艺性状调查结果显示,转基因与未转基因植株之间不存在显著差异,表明转HC-Pro和PMI基因对甘蔗的生长或其他农艺性状没有负面影响。     

美洲商陆抗真菌蛋白转化玉米的研究和抗病性检测

研究美洲商陆抗病毒蛋白(PaAFP)基因转入玉米中对玉米纹枯病的抗性。从美洲商陆叶片中获得美洲商陆抗真菌蛋白前体蛋白基因cDNA序列,构建植物表达载体pCAMBIA1300-PaAFP,通过三亲杂交法将其导入根癌农杆菌LBA4404受体菌,转化玉米获得了大量再生转基因植株。PCR、PCR-southern杂交、RT-PCR以及Tris-Tricine-SDS-PAGE检测结果表明,目的基因已经整合到玉米基因组中,并且已经得到转译。     

亲本材料选择、育种方法及鉴定程序在选育改良品种中的作用(续完)

新的研究途径新的育种程序是根据统计方法估计杂交亲本之间的遗传异质性,如像矮油菜(Brassicacampestris)、高梁、棉花族间杂交的种内异质性杂交。渐渗杂交是利用野生的亲缘植物将其特定的基因转移到栽培类型中去,正如Frey与Browning(1971)于依俄华州所指出的在燕麦属方面获得成功的例子。歧化选择     

优质抗稻瘟病水稻三系不育系M20A的选育

以改良优质三系不育系金山A-1的稻瘟病抗性和配合力作为育种目标,利用携有抗稻瘟病基因Pi-9的金23B抗病近等基因系(04AMA-88)与携有抗白叶枯病基因Xa21的金山B-1抗病近等基因系(04AMA-49)杂交,经分子标记辅助选择,在杂交F4代中选择携带Pi-9的优良单株与金23A测交并转育不育系,育成抗稻瘟病、米质优、配合力好、异交率高的新不育系M20A。该不育系及其配制的杂交早稻新组合M优2155(M20A/明恢2155)于2014年5月通过福建省品种审定委员会审定。     

穗茎注射法导入反义PLDγ基因小麦的分子检测

利用穗茎注射法将反义PLDγ(Antisense phospholipase Dγ)基因导入普通小麦兰考906,并用特异PCR标记和PCR-southern杂交技术对所获得的变异系进行了分子检测,旨在探讨该基因在小麦中的整合效果。结果表明:(1) 经反义PLDγ基因的特异PCR标记,变异系03039、03048和03050扩增出与阳性质粒大小相同的400 bp的目的片断,PCR-southern杂交结果与其一致。说明该基因已整合到小麦的基因组中,从而获得了转反义PLDγ基因的小麦。(2) 转基因株系的成熟期比对照提前4～8 d,后代中易产生雄性不育现象。     

利用农杆菌介导法将BrCS基因导入大豆的研究

以大豆子叶节作为外植体,通过农杆菌介导法将含有BrCS基因的pCAMBIA3300的双子叶植物表达载体,导入到大豆品种黑农59和黑农53中,并对黑农59遗传转化的影响因素进行了优化,最终获得了抗性植株.经PCR检测和PCR-Southern杂交分析,初步证明了目的基因已整合到大豆的基因组中.     

大豆线粒体细胞色素b基因的克隆及系统分析

根据实验室测序的大豆线粒体基因组片段设计线粒体细胞色素b(Cytochrome,cob)基因特异引物,PCR扩增获得1173 bp大豆(JLGM-1B)线粒体cob基因保守区序列.经序列分析,该基因编码391个氨基酸,A+T含量58.1％,G+C含量41.9％.Southern杂交表明cob基因在栽培大豆线粒体基因组中...     

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).