微波消化-等离子体发射光谱仪法分析稻米中无机元素含量的研究

利用微波消化、电感耦合等离子体光谱法(ICP-AES)对稻米中20种无机元素进行了同步定量测定。微波消化与常规温消化法相比较,结果无显著差异。20种元素的平均检出限为0.0426μg/g,回收率在85～104%之间,变异系数平均为1.62%;与NBS等标准物进行了对比,显示出准确度、精密度、灵敏度均较理想。分析测定了51个优质米,结果表明符合质控要求。本方法消化样品快速、完全、污染少,仪器测定灵敏度高、重演性好,适合于稻米及其它生物、环境样品中无机元素含量的检测。     

微波消化-等离子体发射光谱仪法分析稻米中无机元素的研究

 利用微波消化、电感耦台等离子体光谱法(ICP-AES)对稻米中20种无机元素进行了同步定量测定．微波消化与常规湿消化法相比较，结果无显著差异。20种元素的平均检出限为0.0426 μg/g，回收率在85～104%之间，变异系数平均为1.62%；与NBS等标准曲进行了对比，显示出准确度、精密度、灵敏度均较理想。分析测定了51个优质米，结果表明符合质控要求。本方法消化样品快速，完全，污染少，仪器测定灵敏度高、重演性好。适合于稻米及其它生物、环境样品中无机元素含量的检测。     

在线凝胶渗透色谱-气相质谱法检测小麦粉中的50种农药残留

建立在线凝胶渗透色谱-气相质谱分析小麦粉中50种农药残留的方法。样品经乙腈超声提取，提取液经GPC-GCMS在线净化、分离和检测，方法的加标回收率为73.06%～119.9%，相对标准偏差为0.88%～11.02%。方法的检出限为0.000 3～0.009 mg/kg，该方法样品前处理简单、快速、灵敏度高、重现性好，能够满足农药多残留检测技术的要求。     

用高效液相色谱法测定玉米中磺草酮残留量的研究

采用高效液相色谱(HPLC)建立了磺草酮在玉米植株及子粒中残留量的测定方法。试验对样品前处理和色谱条件进行了研究和优化,玉米植株和子粒的添加水平为0.05～0.50 mg/kg,植株中平均回收率为83.15%～86.15%,相对标准偏差为1.44%～2.34%;子粒中平均回收率为80.44%～81.99%,相对标准偏差为1.27%～1.75%。在上述添加水平范围内,测得磺草酮的线性关系良好。该方法具有操作简单、试剂用量少、方法检出限低、回收率高等优点,可满足对玉米中磺草酮残留量的检测需要。     

微波消解-石墨炉原子吸收光谱法测定花生中镉含量

本文研究了高脂肪高蛋白材料花生中镉含量测定方法.采用微波消解法处理花生样品,使用石墨炉原子吸收光谱法测定花生中镉含量.从广东、湖北和辽宁3省随机抽取收获的9个花生样品进行检测,镉含量范围为0.061～0.529mg/kg,RSD为1.22%～8.75% (n =6,c=0.859～7.409ng/mL),该方法检出限为...     

磁固相萃取-气相色谱法检测黄瓜中丙溴磷

复杂样品前处理极大的影响分析结果的准确度和分析过程的时效性,因此建立高效的分离分析方法提高检测的准确性和效率具有重要意义。本研究通过一步水热法,合成了碳包覆四氧化三铁磁性纳米粒子（Fe₃O₄@C-Magnetic nanoparticles,Fe₃O₄@C-MNPs）,利用透射电子显微镜（transmission electron microscope,TEM）、扫描电子显微镜（scanning electron microscope,SEM）、X射线衍射（X-ray diffraction,XRD）、X射线光电子能谱（X-ray photoelectron spectroscopy,XPS）、傅立叶变换红外光谱（Fourier transform infrared spectroscopy,FTIR）、振动样品磁强计（vibrating sample magnetometer,VSM）考察材料的形貌、结构以及磁性能,并以Fe₃O₄@C-MNPs作为磁性吸附剂,构建磁固相萃取-气相色谱法用于黄瓜中丙溴磷的定量检测,优化了影响磁固相萃取过程农药回收率的主要因素,即磁性吸附材料用量、萃取时间和溶液pH。结果表明：合成的Fe₃O₄@C-MNPs表面有丰富的官能团,粒径分布均匀,分散性好,具有超顺磁性,对有机磷农药（organophosphorus pesticides,OPs）丙溴磷有较好的吸附富集效果;最优条件下,即Fe₃O₄@C-MNPs磁性吸附剂用量0.06 g、溶液pH 6、吸附平衡时间10 min、洗脱剂为丙酮时,检测丙溴磷农药的线性范围在0.011~1.0 µg/mL,检出限为0.0011 mg/kg;使用合成的磁性吸附剂材料Fe₃O₄@C-MNPs用于磁固相萃取-气相色谱法检测黄瓜实际样品中丙溴磷,回收率在95.0%~101.4%,相对标准偏差（relative standard deviation,RSD）为2.9%~8.5%。该方法有机试剂用量少,吸附剂可重复利用,降低检测成本的同时也更环保,检测效率也得到提高,检测结果准确可靠。     

PCR检测转基因玉米及其粗加工食品

本研究应用PCR技术对转基因(GM)玉米及其粗加工食品如:爆玉米花、熟玉米棒、速溶玉米片中通常转入的基因构建元件35S启动子、NOS终止子和外源抗虫GryIA(b)目的基因进行检测;对GM玉米的检测低限可达到0.1%;设计征服玉米自身醇溶贮藏蛋白(ZEIN)基因的扩增和阳阴性样品对照、试剂空白质控,可避免假性结果。     

一种快速提取玉米基因组DNA的方法

实验以SDS为主要提取试剂,建立了用于玉米叶片基因组DNA的微量快速提取方法。结果表明:利用此方法提取的玉米叶片基因组DNA具有使用药品少、操作简单、迅速、成本低等优点,每人每工作日可以提取180～250个DNA样品,一个样品可供80～100次PCR反应使用。此DNA提取方法可有效用于玉米的转基因成分检测。     

基于壳聚糖/氧化石墨烯/硅藻土固相萃取-液相色谱串联质谱测定茶叶中多种农药残留

利用前期合成的壳聚糖/氧化石墨烯/硅藻土固相萃取柱高效吸附茶叶基质,结合超高效液相色谱串联质谱（UPLC-MS/MS）,建立了茶叶中46种农药残留的分析方法。茶叶样品经乙腈提取,固相萃取柱净化,乙腈淋洗等样品前处理,UPLC-MS/MS分析46种农药残留。结果表明,该新型固相萃取净化柱可以高效吸附去除茶叶基质,大大降低基质效应,绿茶、红茶和乌龙茶中农药的基质效应分别下降了4.7%~66.5%,3.2%~35.5%和4.4%~42.8%。在3个加标水平下,46种农药回收率在61.5%~118%线性良好,相关系数（R²）均大于0.98。所建立方法具有吸附剂用量少、省时、无需基质标准溶液、可以检测不同茶类多农残和定量限低等优点。     

大豆和玉米加工产品中外源转基因成分检测技术的建立

采用PCR技术检测CaMV 35S启动子,并进一步通过PCR检测RoundUp Ready Soybean(RRS)和Btl76 Maximaizer的特异性DNA片段,判断大豆和玉米加工产品中是否含相应转基因成分.在1份豆粕和豆腐样品中检测到了RoundUp Ready大豆特异性的498 bp片段,而在玉米粒样品中检测到了Btl76特异性转基因成分.PCR检测的灵敏度达到0.1%,稳定性良好.结果表明,PCR技术检测外源基因是灵敏和准确的,可以广泛地应用到转基因作物及其加工产品的转基因成分检测中.     

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.     

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.     

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.