我国转基因棉花研究与应用进展

我国转基因棉花研完近10年，取得重大进：研制出单价Bt和双价Bt/CpTI转基因抗虫棉。已审定的品种正在生产上大面积推广，累计达160khm^2；建立了Bt棉的遗传育种、栽培、良种繁育、抗虫性鉴定、棉铃虫的抗性治理、棉田害虫综合防治以及安全性评估等一整套技术体系；棉花抗病基因工程和棉纤维品质改良的基因工程也取得了进展。     

农杆菌介导的花生遗传转化研究

对影响花生遗传转化效率的PPT筛选压、根癌农杆菌的侵染浓度、侵染及共培养时间等因素进行研究，采用农杆菌转化花生叶片，成功地将抗虫基因豇豆蛋白酶抑制基因(CpTI)和耐除草剂基因(Bar)导入花生。实验结果表明，外植体在MS 3mg／LBA 0．8mg／LNAA 2mg／LAgNO3 6mg／L Gln培养基上预培养3d，于OD600为0．3的农杆菌菌液中浸泡5～7min后培养2d，再转移至含有3mg／LBA 0．8mg／LNAA 2mg／LAgNO3 6mg／L Gln 500mg／LCb 300mg／LCef 0．25mg／LPPT的MS培养基诱导筛选培养，3个月后得到24个再生株系。经PCR初步检测，有7个株系显示了310bp的CpTI基因核酸片段，Southern杂交证实了5个株系有外源基因的整合。     

基因枪轰击成熟花粉粒转化玉米的研究

研究了利用基因枪轰击花粉粒再授粉的基因转化途径,将豇豆胰蛋白酶抑制剂基因穴CpTI雪成功导入玉米受体中。卡那霉素筛选结果表明,非转化植株经1000mg/kg卡那霉素溶液处理后白化、死亡,余下大量健壮、可育的抗性植株,转化率约1.59%。通过对抗性植株进行PCR和PCR-Southern检测,初步确定CpTI基因已导入玉米基因组。饲虫实验结果表明,转化植株具有较强的抗虫性。     

花生遗传转化的研究

介绍了国内外近１０年花生遗传转化的研究现状,着重介绍了花生遗传转化目的的基因的来源和基因导入的常用方法,以及高效的转基因再生系统。     

转基因花生外源基因田间漂移风险初步研究

用含花生条纹病毒壳蛋白(cp)基因和潮霉素(hygr)筛选基因的转基因花生品系为材料,田间试验表明转基因花生中的hygr基因可在短距离范围内随花粉漂移,离转基因花生种植区边缘1.0m 和3.0m范围内漂移频率分别为4.4%和5.0%;3.0 m以外范围内,没有检测到hygr基因随花粉漂移发生。各距离范围内均没有检测到cp基因随花粉漂移现象。因此认为,转基因花生外源基因漂移距离在3.0m以内。     

转基因花生对根瘤菌的影响和外源基因向根瘤菌逃逸风险性研究

用含花生条纹病毒壳蛋白基因的转基因花生品系TP-1、TP-7为材料,通过水培生长试验表明在花生不同生长时期,转基因花生对单株花生根瘤菌结瘤数量和结瘤重量无明显影响.对从转基因花生品系TP-1、TP-7上分离的100个根瘤菌样品PCR检测结果,花生根瘤菌中无花生条纹病毒壳蛋白基因特异性片断.结果初步说明导入花生的花生条纹病毒壳蛋白基因不会对根瘤菌结瘤生长特性产生影响,外源基因从花生向根瘤菌逃逸的机率很小.     

转甘蔗抗虫基因CpTI的RT-PCR检测

利用已修饰的CpTI基因进行转基因检测,根据修饰后的目的基因片段序列对两个甘蔗品种(P44和福农94-0403)的转基因甘蔗进行RT-PCK检测研究,结果在被检测的10 株甘蔗中验证了3株已转入植株中,RT-PCR检测到的20、25、26号植株均呈阳性,证明被修饰的sck基因已成功转入甘蔗.     

转cry 1Iem基因大豆的培育及抗虫性检测

以大豆子叶节为外植体,应用农杆菌介导法,将抗虫(cry1Iem)基因转化大豆.筛选标记为bar基因.经Glufasinate筛选,获得大量抗性植株.对转基因T_0、T_1、T_2代植株进行PCR检测,初步证明cry1Iem基因已经整合到大豆基因组中.对T2代PCR阳性植株幼嫩豆荚,采用圆盘分隔法接人初孵幼虫,进行初步的抗虫性检测,得到1株具有明显抗虫效果和7株抗虫效果较好的转基因植株.     

sbk和sck双价抗虫转基因水稻的育成和鉴定

 将包含2个抗虫基因sbk\[修饰后的Cry1A(c)\]和sck（修饰后的CpTI）的质粒载体pCDMARUBA Hyg转入农杆菌EHA105中, 感染南粳45的愈伤组织, 得到再生植株。用sbk和sck基因的引物进行PCR分析, 从97个再生植株中筛选出42个含有2个抗虫基因而没有潮霉素基因的阳性植株。通过Southern杂交发现, 42个阳性植株中具有1~5个外源基因拷贝的分别有23、 11、 5、2和1个单株。用RT PCR检测发现, 4个单拷贝株衍生的28个T3代植株外源基因能正常表达。人工饲喂二化螟幼虫试验也表明, 转基因植株的幼虫死亡率达94%~100%, 抗虫能力比对照显著提高。筛选出3个农艺性状优良的株系。     

可去除选择标记的转CpTI基因抗虫玉米研究

将组成型表达的玉米泛素启动子与豇豆胰蛋白酶抑制剂基因CpTI连接,插入根癌农杆菌双T-DNA质粒,构建一个T-DNA结构域含有抗潮霉素选择标记基因hyg;另一个T-DNA结构域含有抗虫基因的双T-DNA单子叶植物表达载体,用以转化农杆菌菌株,再通过共培养转化玉米胚性愈伤组织。通过潮霉素培养基抗性筛选,用特异PCR扩增和Southern杂交检测,从分化再生的T0代植株中,鉴定出7个转化CpTI基因的阳性植株。目前,正结合进行田间分离纯合和DNA分子鉴定,培育去除选择标记基因的转基因抗虫玉米自交系。     

Mineral composition of some traditional Mexican teas

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots ofTagetes lucida, T. filifolia, Elytraria imbricata, andHolodiscus dumosus, and from root xylem ofCeanothus depressus andPhaseolus ritensis. Native uses of these teas are also described.     

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.     

Redox Status and Neuro Inflammation Indexes in Cerebellum and Motor Cortex of Wistar Rats Supplemented with Natural Sources of Omega-3 Fatty Acids and Astaxanthin: Fish Oil,Krill Oil,and Algal Biomass

Health authorities worldwide have consistently recommended the regular consumption of marine fishes and seafood to preserve memory, sustain cognitive functions, and prevent neurodegenerative processes in humans. Shrimp, crabs, lobster, and salmon are of particular interest in the human diet due to their substantial provision of omega-3 fatty acids (n-3/PUFAs) and the antioxidant carotenoid astaxanthin (ASTA). However, the optimal ratio between these nutraceuticals in natural sources is apparently the key factor for maximum protection against most neuro-motor disorders. Therefore, we aimed here to investigate the effects of a long-term supplementation with (n-3)/PUFAs-rich fish oil, ASTA-rich algal biomass, the combination of them, or krill oil (a natural combination of both nutrients) on baseline redox balance and neuro-inflammation indexes in cerebellum and motor cortex of Wistar rats. Significant changes in redox metabolism were only observed upon ASTA supplementation, which reinforce its antioxidant properties with a putative mitochondrial-centered action in rat brain. Krill oil imposed mild astrocyte activation in motor cortex of Wistar rats, although no redox or inflammatory index was concomitantly altered. In summary, there is no experimental evidence that krill oil, fish oil, oralgal biomass (minor variation), drastically change the baseline oxidative conditions or the neuro-inflammatory scenario in neuromotor-associated rat brain regions.     

Potential of dry fractionation of wheat bran for the development of food ingredients,part II: Electrostatic separation of particles

Wheat bran is a composite material made of several layers, such as pericarp, testa and aleurone. It could be fractionated into purified fractions, which might either be used as food ingredients, or serve as a starting material for extraction of bioactive compounds. The aim of this work was to evaluate the potential of using electrostatic separation as a way to obtain purified fractions from wheat bran. Ultrafine-ground bran obtained either by cryogenic grinding or by grinding at ambient temperature was used as starting material. The ultrafine bran was then charged by tribo-electrification and introduced in a chamber containing two high voltage electrodes, where bran particles were separated depending on their acquired charge, allowing positively and negatively charged fractions to be collected separately. The particle size distribution, microstructure and biochemical composition of the obtained fractions were studied. The charge of the particles was influenced by their biochemical composition: particles rich in highly branched and cross-linked arabinoxylans (pericarp) were separated from particles rich in β-glucan, ferulic acid and para-coumaric acid (aleurone cell walls). The testa and the intracellular compounds from aleurone were not highly charged, neither positively nor negatively. The most positively charged fraction represented 34% of the initial bran, and contained 62% of the ferulic acid present in the initial bran. The yield of the separation process was good (5.4% loss), and could be further increased.     

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.     

<Emphasis Type="Italic">Pulque</Emphasis>, An Alcoholic Drink from Rural Mexico,Contains Phytase. Its <Emphasis Type="Italic">in vitro</Emphasis> Effects on Corn Tortilla

Pulque is made by fermenting the agave sap or aguamiel of Agave atrovirens with a whole array of microorganisms present in the environment including several lactic acid bacteria and yeasts such as Saccharomyces cerevisiae. Ascorbic acid was determined in pulque and aguamiel, respectively. Phytase activity in lees, liquid and freeze-dried pulque was assayed by measuring the appearance of phosphate from phytate by a colorimetric method likewise phosphate from phytate present in fresh corn tortilla was measured after in vitro incubation with pulque. Iron, zinc, calcium, magnesium and selenium contents were measured in pulque and corn tortilla as well as in nixtamalized corn flour (NCF), the latter is used to make instant tortilla, since corn provides most of the energy as well as most of the phytate in the Mexican rural diet. Pulque showed phytase activity but much less ascorbic acid and iron than previously reported; additionally, phytase in pulque hydrolyzed most of phytate’s corn tortilla. Lees, which is mostly made of pulque’s microbiota, significantly accumulated iron and zinc but no selenium. NCF was fortified with iron by the manufacturers but poorly blended. There were significant differences on selenium content between tortillas samples, apparently some soils in central Mexico are selenium deficient. Moderate pulque intake appears to increase the bioavailability of iron and zinc bound by phytate in corn.