番木瓜ζ-胡萝卜素脱氢酶基因时空表达的荧光定量PCR分析

ζ-胡萝卜素脱氢酶(ZDS)是类胡萝卜索生物合成过程中的关键酶之一,它催化ζ-胡萝卜素转化成链孢红索,并催化链孢红素向番茄红素的转化.ZDS是限速酶,在植物果实颜色和花色发育过程中起着重要作用.本研究以番木瓜黄果品种DwaIf solo和红果品种Sunrlse solo为材料,采用实时荧光定量PCR SYBR Green I荧光染料法,对2个番木瓜品种的不同组织器官及果实发育成熟过程中的ZDS基因在转录水平上的表达进行了相对定量分析.结果表明,2个番木瓜品种的果实、花、叶片中均可检测到ZDS基因在转录水平上的表达,但表达量存在组织和部位上的差异.ZDS基因在成熟果实中的表达量比花中的高,花中的比叶中的高.ZDS基因在Sunrise solo (红果肉)番木瓜果实发育成熟过程中的表达逐渐增强,且变化显著,而在Dwarf solo(黄果肉)番木瓜果实早期表达增强,成熟后期则表达趋为稳定.2个番木瓜品种成熟果肉中ZDS基因表达量存在差异,红果肉中的表达量高于黄果肉.     

番木瓜NAC转录因子的克隆与表达分析

为探究番木瓜NAC转录因子的序列特征及功能,以‘大庆7号’番木瓜果肉为试验材料,采用RTPCR克隆出2个不同的NAC类基因,命名为CpNAC1(Gene Bank KT364871)和CpNAC2(Gene Bank KT372241),其开放阅读框(ORF)长度分别为609 bp和805 bp,分别编码202个和268个氨基酸,其N端含有NAM保守结构域。采用实时荧光定量PCR研究其在乙烯利及清水对照处理后果实不同成熟时期中的表达情况,结果发现,CpNAC1和CpNAC2基因随着处理后时间的增加,表达量呈先下降后缓慢上升的趋势,且均与果实成熟呈负相关。但CpNAC1表达趋势与果实成熟过程中乙烯的表达量相反,受乙烯抑制降低表达量,从而参与了番木瓜果实的成熟衰老进程,而CpNAC2基因在乙烯处理后番木瓜果实中表达量与对照处理相比没有显著变化,说明CpNAC2基因不是通过乙烯信号传导途径来调控果实成熟。     

番荔枝中一个SWEET家族基因的克隆与表达分析

以番荔枝不同组织样品为材料,通过基因文库筛选,利用RT-PCR技术克隆出1个1227 bp的基因,命名为AT-SWEET16-1,该基因编码408个氨基酸,该氨基酸序列在N端以α螺旋形成THB结构域。生物信息学分析结果表明,该蛋白分子量为44.8 kDa,等电点为8.87。进化分析结果发现其与海枣（Phoenix dactylifera）相类聚。qRT-PCR分析结果表明,该基因在植株的根、茎、嫩叶、老叶、花蕾、花苞、幼果、成熟果中均有表达,AT-SWEET16-1基因在不同组织中的表达量依次是：成熟果>茎>根>花蕾>幼果>老叶>嫩叶;该基因在不同果实发育阶段中的表达情况为：在果实不同发育阶段,果柄中的表达量最高,果肉、果皮中则相对较低,种子中最低;但果实成熟期该基因在果柄、果肉中的表达量最高。原位杂交实验观察发现,基因表达位置为果柄韧皮部、果肉细胞膜间,结合基因表达分析结果,预示该基因在植株糖分积累与转运等方面起到一定的作用。     

沙田柚果实PIP基因的克隆及其表达分析

采用 RT-PCR 和 RACE-PCR的方法，从沙田柚果实中分离得到1个CgPIP2基因全长序列，编码284个氨基酸，与其它物种质膜水通道蛋白氨基酸序列比较结果表明，它们之间具有较高的同源性，且均具有水通道蛋白家族蛋白的特征结构单元 NPA。采用烘干法测定贮藏期间沙田柚果实含水量的变化。结果表明：在沙田柚果实贮藏过程中，果皮和果肉的含水量逐步下降，且单果包装对果实含水量有一定的影响。半定量RT-PCR分析表明，CgPIP2 在沙田柚果实的果皮和果肉中都有表达，随着贮藏期的延长表达逐渐减弱，但在果肉中的表     

3个香蕉品种黄酮含量与果实发育成熟的关系

为了明确香蕉果实发育及成熟过程中黄酮含量变化规律,对巴西香蕉、粉蕉和皇帝蕉果实采前发育和采后成熟过程中的黄酮含量进行测定。结果表明:3个香蕉品种在果实发育成熟过程中果皮中黄酮含量均显著高于果肉中黄酮含量。从抽蕾、断蕾到采收,3个品种果皮中的黄酮含量逐渐降低,表现出与发育负相关。采前巴西蕉和黄帝蕉果肉中黄酮含量也是逐渐降低,但粉蕉果肉中黄酮含量呈先升后降的趋势。在采后成熟过程中,3个香蕉品种果皮果肉中的黄酮含量逐渐升高。且用外源乙烯和1-MCP处理后发现,香蕉果皮和果肉中的黄酮含量明显受外源乙烯诱导而增加,受1-MCP的抑制而减少,表现出与成熟正相关。     

妃子笑荔枝果实发育过程中相关指标分析

以荔枝品种妃子笑(Litchi chinensis Sonn.cv.Feizixiao)为材料,通过测定其果实发育过程中重量、体积、糖、酸、维生素C(Vc)、丙二醛(MDA)含量、超氧化物歧化酶(SOD)及过氧化物酶(POD)活性的变化,分析该品种果实的发育特性。结果表明:花后40 d到果实着色阶段为妃子笑果肉发育与风味形成的最重要时期,此阶段果肉开始膨大,糖含量升高,酸含量降低。除此之外,果实发育过程中果皮和果肉可能具有不同的清除自由基模式。果皮中膜脂过氧化产物MDA含量相对稳定,但随着果实的发育,果皮内3种主要的抗氧化功能组分变化不一,其中Vc含量和SOD活性逐渐下降,POD活性则逐渐上升。与果皮不同,果肉中MDA含量随果实的发育逐渐下降,说明果肉清除自由基的能力随果实发育逐渐提高,而此过程中,果肉Vc含量显著上升,SOD活性下降,POD活性相对稳定。此结果表明果实发育过程中,果肉抗氧化能力的提高与Vc含量上升直接相关。     

西施柚果发育过程中金属营养元素生理研究

研究西施柚果实发育过程K、Ca、Mg、Zn、Cu、Mn、Fe共7种金属营养元素的含量与分布、吸收规律及其与活性氧代谢的相关性.结果表明:(1)4～6月、6～8月和8～10月分别是果皮迅速生长期、果肉迅速生长期和果实转色成熟期.(2)果皮和果肉中K、Mg、Zn、Cu、Mn、Fe的含量均随果实的发育总体呈递减规律(果皮中Ca的含量相反),但7种元素的吸收总量则不断增加.K含量位居7种元素之首.K、Zn、Fe以果肉居多,Ca、Mg、Mn主要分布在果皮,Cu在果皮果肉中的含量相当.(3)7种元素的累积主要集中在6～8月果肉迅速增长期,K、Ca和Fe在10月果实成熟期也有较大的吸收.K的吸收率与单果重增长率呈极显著正相关,Ca和Fe与单果重、Mg和Cu与果肉直径呈显著正相关.(4)7种元素中K与其它元素的相关性显著率较高,Ca和Cu以负相关为主.(5)Mn和K与活性氧代谢指标相关性较显著,其次是Zn、Fe和Mg,Ca和Cu均不显著.     

模拟低温对龙眼果实发育及其果皮H_2O_2代谢的影响

以3年生‘储良’龙眼盆栽树为试验材料,于花后28 d时采取模拟低温(昼夜15/10℃)处理,研究该处理对龙眼果实发育及其果皮过氧化氢(H_2O_2)含量、过氧化物酶(POD)活性与过氧化氢酶(CAT)活性的影响,以常温(昼夜28/23℃)处理为对照。结果表明:模拟低温处理后的龙眼成熟果实单果重明显偏小、发育期显著增加,主要是延长了果实发育前期,但其累积落果率与对照差异不显著。模拟低温期间,果实生长缓慢,落果较少,果皮POD、CAT活性与H_2O_2含量均低于对照;但从处理后43 d起开始解除模拟低温后,果实发育迅速,落果剧烈,果皮POD、CAT活性及H_2O_2含量均呈先升后降的变化趋势,且在果实发育中后期均明显高于对照。这表明,模拟低温抑制了果实生长、延长了果实发育期,温度骤然回升引起果皮H_2O_2的爆发及果皮抗氧化酶活性的提高,进而诱导了果实大量脱落。     

哈姆林甜橙蔗糖合酶Ⅰ和酸性转化酶基因表达与果实糖积累的关系

蔗糖合酶(Sucrose synthase,SS)与酸性转化酶(Acid invertase,AI)是甜橙糖代谢过程中的两个关键酶,SS催化尿嘧啶核苷二磷酸葡萄糖和果糖合成蔗糖的可逆反应,AI则不可逆的催化蔗糖分解为果糖和葡萄糖,它们在甜橙糖代谢过程中起着重要作用。笔者以哈姆林甜橙品种为试验材料,采用半定量RT-PCR法,对4个时期哈姆林叶片中的SSI基因和AI基因的表达进行了分析。结果表明,4个时期哈姆林叶片中均可检测到SSI基因和AI基因在转录水平上的表达,但表达量存在差异。SSI基因在果实发育过程中表达量呈"低-高-低-高"趋势。AI基因在哈姆林果实发育成熟过程中的表达逐渐减弱,与果实糖累积呈负相关。     

锌对砂糖橘果实发育过程细胞壁代谢的影响

为研究不同锌处理对砂糖橘果实发育成熟过程中果皮硬度、细胞壁结构物质及其相关酶活性的影响,以四年生砂糖橘（Citrus reticulata Blanco cv. Shatangju）为试材,在果实膨大期喷施不同锌肥,同时对与果皮力学性能相关的细胞壁代谢变化规律进行分析。结果表明,不同锌处理均可降低果实发育成熟过程中果皮硬度的变化幅度,降低多聚半乳糖醛酸酶（PG）、纤维素酶（Cx）、果胶甲酯酶（PE）的活性,其中Zn2++Ca2+处理的果皮硬度变化最均匀、陷痕果高发期Cx和PE活性低、原果胶和纤维素含量高。不同锌处理均可有效地降低果实发育成熟过程中细胞壁代谢酶的活性,抑制原果胶和纤维素的降解,延缓细胞壁水解,使得果实硬度变化更均匀,其中Zn2++Ca2+处理的效果最明显。     

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.     

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.     

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.     

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.     

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).     

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).     

Pharmacokinetics of Marine-Derived Drugs

Marine organisms represent an excellent source of innovative compounds that have the potential for the development of new drugs. The pharmacokinetics of marine drugs has attracted increasing interest in recent decades due to its effective and potential contribution to the selection of rational dosage recommendations and the optimal use of the therapeutic arsenal. In general, pharmacokinetics studies how drugs change after administration via the processes of absorption, distribution, metabolism, and excretion (ADME). This review provides a summary of the pharmacokinetics studies of marine-derived active compounds, with a particular focus on their ADME. The pharmacokinetics of compounds derived from algae, crustaceans, sea cucumber, fungus, sea urchins, sponges, mollusks, tunicate, and bryozoan is discussed, and the pharmacokinetics data in human experiments are analyzed. In-depth characterization using pharmacokinetics is useful for obtaining information for understanding the molecular basis of pharmacological activity, for correct doses and treatment schemes selection, and for more effective drug application. Thus, an increase in pharmacokinetic research on marine-derived compounds is expected in the near future.