快中子辐照对花生种子胚小叶植株再生的影响

以花生品种花育22号的成熟饱满种子为试材,采用14Mev不同剂量的快中子(0、9.7、14和18Gy) 进行辐照处理。处理后的种子经表面杀菌后,取胚小叶作为外植体先后在添加2,4-D 和BAP 的培养基上进行培养,诱导体胚形成及其萌发和植株再生。结果表明,体胚诱导率和植株再生率因辐照剂量的不同表现出明显的差异,随辐照剂量的增加,外植体形成体胚的频率及再生植株的频率明显降低。推断快中子辐照花育22号的适宜剂量为9.7~14.0Gy。再生小苗经无菌嫁接驯化后移栽田间,得到了成熟种子。           

黑麦6R染色体特异性PCR标记的建立

为了筛选黑麦染色体组特异性分子标记,以荆州黑麦、秦岭黑麦、森林黑麦、非洲黑麦、普通小麦中国春、R25、R111和MY11为材料,用A～M组142个10碱基随机引物进行RAPD扩增.发现引物M04可以在所有黑麦中扩出一条长1 143 bp(经测序)的特异片段OPM041143,而供试小麦材料均未扩出该片段.根据OPM041143设计特异引物M4-F和M4-R.利用M4-F和M4-R对含黑麦染色体的材料和小麦族其它物种进行扩增,结果表明,只有含黑麦染色体的材料均可以扩出一条分子量为1 082 bp的DNA带,命名为PSCM1082.进而利用一套中国春-Imperial黑麦二体附加系和几个小麦-黑麦染色体6R衍生系进行扩增,发现仅含6R染色体的材料能扩增出PSCM1082,这说明PSCM1082是黑麦6R染色体所特有.黑麦6R染色体特异PCR标记PSCM1082的发现,对于快速跟踪检测导入小麦中的6R染色体具有实用价值,可以应用于小麦育种工作中.     

黑麦染色体1R和5R单体附加诱导的小麦和黑麦染色体的变异和易位

利用普通小麦品种绵阳11作母本,抗病的威宁黑麦(Sceale cereale L.)作父本,在其杂交和回交后代中分别鉴定出一个1R和5R单体附加系。为获得新的1BL·1RS初级易位系以及小麦-黑麦5R染色体易位,采用基因组原位杂交和荧光原位杂交相结合的方法,对1R和5R单体附加系的自交后代进行了鉴定。在1R单体附加系的后代中,筛选到一个纯合1R(1B)染色体代换系和一个新的纯合1BL·1RS初级易位系。该1R(1B)代换系表现出比小麦亲本较差的农艺性状;新1BL·1RS初级易位系表现出比其小麦亲本更好的农艺性状以及条锈病和白粉病抗性,而且穗粒数显著增加,是高产抗病小麦育种的新资源。在5R单体附加系的后代中,筛选出一个涉及3BS染色体片段与5RL的易位,发生易位的植株占分析植株总数的1.89%。5R染色体单体附加极其不稳定,在一个世代交替中完整的5R染色体传递率仅有28.3%。除自身的不稳定外,5R染色体单体附加同时导致小麦染色体7B、3B和4D的断裂和丢失,总变异频率达到15.09%;尤其对7B染色体影响较大,含7B染色体变异的植株占分析植株总数的11.32%。5R染色体单体附加诱导的小麦和黑麦染色体的高度不稳定现象值得进一步研究。     

抗条锈病普通小麦-滨麦6BS·6NsS附加易位系的分子细胞遗传学鉴定

易位系是向小麦转移外源种属优异基因的重要种质资源。普通小麦-滨麦衍生系M13063A-1由小麦-滨麦第六部分同源群二体异附加系材料连续自交获得。为了给普通小麦-滨麦衍生系M13063A-1的利用提供依据,本研究利用形态学、细胞学、原位杂交、分子标记等技术,对该材料进行了鉴定。细胞学鉴定结果显示,M13063A-1有丝分裂中期染色体数目为44条,减数分裂中期I染色体构型为2n=22Ⅱ,且在减数分裂后期Ⅰ可均等分离。原位杂交结果表明,M13063A-1含有42条普通小麦染色体和1对普通小麦-滨麦易位染色体,易位染色体长臂为滨麦Ns基因组染色体片段,短臂为6BS。分子标记分析确定M13063A-1携带的滨麦染色体片段为6NsS。成株期条锈病抗性鉴定显示,M13063A-1抗条锈菌生理小种条中31和条中32。因此,M13063A-1是一个抗条锈病的普通小麦-滨麦6BS·6NsS附加易位系,可以用作小麦抗病育种的桥梁材料。     

小麦外源基因转移的最新进展（续）

小麦外源基因转移的最新进展（续）ＪｉｍｉｎｇＪｉａｎｇ等小麦外源染色体易位的鉴定小麦外源染色体易位的鉴定包括鉴别发生易位的染色体、断裂位点和估测转移的异染色质数量。虽然常规技术如染色体配对分析可提供重要信息，但不适于鉴定小麦外源易位，特别是中间易位和...     

小麦染色体转入黑麦的研究进展

十多年来，德国的Ｓｃｈｌｅｙｅｌ和Ｍｅｌｚ等人从进行黑麦改良的目的出发，致力于将小麦染色体转入黑麦的工作，已获得具有１０个小麦胞质的黑麦－小麦附加系，８个具有黑麦胞质的黑麦－小麦附加系。这些附加系在形态上与黑麦基本相似，其生活力因胞质的不同：具有小麦胞质的附加系生活力弱，分蘖少，结实性差；具有黑麦胞质的附加系生活力、分蘖性基本正常，结实性亦较好。在小麦染色体的传递性方面，两种胞质的附加系都表现低频率。利用获得的附加系，定位了３个小麦基因：控制叶茎部紫色性状的基因Ｒａ２和Ｒａ３分别位于４Ｂ和６Ｂ上；控制过氧化氢酶的Ｃａｔｌ位点位于４ＢＬ上；对Ｐｈ１基因在黑麦传递背景下的表达进行了研究，Ｐｈ１对黑麦染色体的配对具有抑制作用。另外，采用辐射手段进行了染色体的易位研究，将６ＢＬ易位到黑麦染色体组上，此项工作是在二倍体水平上进行染色体工程操作的一个新探索。     

小麦SSR引物扩增黑麦及附加系6R染色体特异DNA片段的克隆

为了获得黑麦特异分子标记以及更加方便地检测导入小麦的黑麦染色质,选用定位于普通小麦7个同源群染色体上的88对SSR引物对11种二倍体黑麦和普通小麦中国春、绵阳11进行PCR扩增,有11对引物能稳定地扩增出较强的、在供试材料间表现出多态性的条带.引物Xgwm232在供试的9种黑麦中扩增出了一条长491 bp的黑麦特异片段(命名为pMD232-500),而供试小麦与其余两种黑麦均未扩增出该片段.用该引物对两种小麦－黑麦双二倍体CI、HK及衍生自CI、HK的两套小麦－黑麦附加系进行扩增,发现在CI和HK中都能扩增出该片段,而在两套附加系中都只有6R染色体能扩增出该片段.将从6R附加系中扩增出的片段进行克隆测序,结果表明该片段(命名为pMD2326R-500)与pMD232-500的相似性达99％.因此,该引物可以用来跟踪导入小麦中的部分黑麦的6R染色体.     

小麦背景中黑麦遗传物质的快速检测方法

黑麦(Secale cereale L.)基因资源在小麦(Triticum aestivum L.)品种改良方面具有很大的利用潜力。建立一种高效鉴定小麦背景中黑麦染色体的细胞学标记方法,有利于黑麦优良基因/遗传物质的追溯和高效利用。本研究利用核仁组织区(NOR)核糖体DNA(rDNA)串联重复序列,开发了一种新的寡核苷酸探针Oligo-1RNOR。非变性荧光原位杂交(ND-FISH)试验表明,该探针可专化性识别黑麦1R染色体的NOR区域,并产生强于Oligo-5BL.46的信号。同时,为了提高外源遗传物质细胞学鉴定的效率,建立了一种快速、简便制备小麦间期细胞的方法。利用基于Oligo-1RNOR、Oligo-pSc200和Oligo-pSc250探针的ND-FISH对制备的间期细胞滴片进行分析,结果与中期染色体细胞滴片的FISH结果相同,均能够清楚地判定材料中是否含有黑麦染色体。该方法无需制备中期染色体,叶片和根尖均可用于制备间期细胞,避免了常规细胞学根尖组织制片的预处理和固定程序,为检测小麦背景中的黑麦遗传物质或小麦-黑麦易位染色体提供了更方便的技术手段。本研究建立的方法不足之处在于...     

小麦中外源遗传物质鉴定的研究进展

随着小麦近缘植物外源遗传物质不断导入普通小麦，对小麦中外源遗传物质的鉴定方法的研究不断得到深入。目前，鉴定方法有传统的形态学、细胞遗传学及生化标记与原位杂交、分子标记等。本文从不同层次对这些鉴定方法的研究现状进行了综述，并对其优缺点和应用前景进行了讨论。形态标记简单直观，但其数目少，多态性差；染色体计数和染色体构型分析能反应染色体在结构和数目上的变化，但无法确定外缘染色体的来源与易位位置，且费时费力；染色体分带对带有特征带的整条或大片段易位特别有效，对不显带的小片段无能为力；同工酶和种子贮藏蛋白常被用来鉴定部分同源染色体归属，稳定性好，但其标记的数量比较有限；分子原住杂交能准确鉴定是否含有外缘染色体，但无法明确附加、代换及易位的哪一条外源染色体或染色体片段；RFLP、RADP、AFLP、SSR、SCAR和STS等分子标记以多态性高、不受季节环境影响而被广泛采用，但其在染色体定位上还需与其它鉴定方法相结合。小麦中外源遗传物质鉴定的准确性依赖于以上鉴定方法相互结合，相互验证。     

普通小麦-中间偃麦草易位系08-738的鉴定

中间偃麦草(Thinopyrum intermedium,2n=42)具有大穗多花和抗多种病害等特性,是小麦育种的重要基因资源之一。为确定普通小麦川麦107与中间偃麦草杂交获得的遗传稳定品系08-738的染色体组成,采用形态学、细胞遗传学和SSR分子标记对其进行了鉴定。形态学分析表明,08-738具有植株较矮和小穗数较多的特点。细胞学观察表明,其染色体数目及构型为2n=42=21II。基因组原位杂交(GISH)和重复序列原位杂交(FISH)结果表明,08-738含有20对小麦染色体和1对小麦-中间偃麦草小片段易位染色体,易位位于小麦3DS的近末端,且该外源片段可能来源于中间偃麦草的Js染色体组。SSR标记分析显示,位于3DS 6-0.55-1.00之间的SSR标记xcfd141能在08-738和中间偃麦草之间扩增出一条特异条带,xcfd141可作为该中间易位片段鉴定和选择的标记。     

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).