Detection of processed genetically modified food using CIM monolithic columns for DNA isolation

The availability of sufficient quantities of DNA of adequate quality is crucial in polymerase chain reaction (PCR)-based methods for genetically modified food detection. In this work, the suitability of anion-exchange CIM (Convective Interaction Media; BIA Separations, Ljubljana, Slovenia) monolithic columns for isolation of DNA from food was studied. Maize and its derivates corn meal and thermally pretreated corn meal were chosen as model food. Two commercially available CIM disk columns were tested: DEAE (diethylaminoethyl) and QA (quaternary amine). Preliminary separations were performed with standard solution of salmon DNA at different pH values and different NaCl concentrations in mobile phase. DEAE groups and pH 8 were chosen for further isolations of DNA from a complex matrix-food extract. The quality and quantity of isolated DNA were tested on agarose gel electrophoresis, with UV-scanning spectrophotometry, and by amplification with real-time PCR. DNA isolated in this way was of suitable quality for further PCR analyses. The described method is also applicable for DNA isolation from processed foods with decreased DNA content. Furthermore, it is more effective and less time-consuming in comparison with the existing proposed methods for isolation of DNA from plant-derived foods.     

Cleansing contaminated seawaters using marine cyanobacteria: evaluation of trace metal removal from the medium

The use of microbial biomass in biosorption is already being studied as a potential alternative to (or combined with) conventional processes, where several algae and microorganisms have already shown promising ability to uptake metals. Cyanobacteria (blue-green algae) are widespread organisms, with specific properties, such as high nutrient removal capacity and tolerance to highly variable conditions which make them well-suited for wastewater and remediation purposes. The main aim of this work was to evaluate the use of a marine cyanobacterium LEANCYA 21 (Synechocystis sp.), collected from the Portuguese southern border, for the removal of selected trace metals when in natural seawater culture medium. It was observed, for the first time, that this particular strain is capable of uptaking Pb, Ni and Zn (at nM levels) from seawater solutions using small amounts of biomass. Uptake values for Pb were up to 90% (0.75 mg g^?1 biomass) in 6 h. The specific biosorption curves of Ni and Zn showed that these metals follow a first order kinetics biosorption in batch conditions. Solutions containing multimetals have revealed that Ni uptake is affected by the presence of Pb and Zn. The calculated specific absorption values were high enough to predict a possible application in aquaculture where such low levels of metals may inhibit microalgae growth.     

A guide for the meaningful surface analysis of wood by XPS and ToF-SIMS

The surface analysis of wood and wood products is becoming increasingly important for reasons ranging from the investigation of molecular constituents through to the optimization of industrial processes. As with any natural product, wood analysis is not straightforward, and this review aims to provide guidance for the successful surface analysis of wood by XPS and ToF-SIMS. Through example experiments, three themes are addressed relevant to obtaining meaningful results: considerations related to heterogeneity in the composition of wood (e.g., growth rings); the impact of the chemical removal of minor wood components known as extractives, and whether such a process is necessary; and the potential for misleading or erroneous results as a result of contamination occurring during sample preparation. In addition to discussing successful sample preparation approaches, the important role to be played by MVA in surface analysis is emphasized, particularly in the analysis of ToF-SIMS data. Examples of ToF-SIMS/MVA are provided that highlight the identification of contamination in sample preparation, the quantification of wood composition in terms of cellulose and lignin, and the indication of age of softwood samples. Through consideration of the complexities that influence wood surface analysis, the design and interpretation of consequential experiments become easier and more accurate.     

QuEChERS提取-高效液相色谱-高分辨质谱法测定水产品中3种蓝藻毒素的含量

取水产品样品2.00g与2g无水硫酸钠混匀后加入提取剂10 mL甲醇,涡旋振荡5min后超声提取5 min,再离心5 min,取其上清液。在上清液中加入500 mg中性氧化铝和15mg石墨化碳黑(GCB)涡旋振荡1min,离心5min,取上清液,于40℃下吹氮至近干,用体积比为1∶1的流动相A-流动相B混合溶液溶解残渣并定容至2.0mL,经0.22μm滤膜过滤,取其滤液按高效液相色谱-高分辨质谱法测定其中3种蓝藻毒素的含量。色谱分离中用Hypersile Gold C8色谱柱(150mm×2.1mm,3μm)为固定相,用不同比例的流动相A和流动相B两溶液的混合液作为流动相进行程序梯度洗脱。质谱测定中采用电喷雾离子源,正、负离子切换模式。由于3种蓝藻毒素均产生基质减弱效应,制作工作曲线需用基质标准溶液以消除基质效应。结果表明:所测3种蓝藻毒素均在10~200μg·L^-1内与其峰面积之间呈线性关系,其检出限(3S/N)均为5μg·kg^-1。通过标准加入法进行回收试验,测得回收率为68.3%~104%,测定值的相对标准偏差(n=6)为7.7%~17%。     

Anti-Inflammatory Dysidazirine Carboxylic Acid from the Marine Cyanobacterium Caldora sp. Collected from the Reefs of Fort Lauderdale,Florida

Dysidazirine carboxylic acid (1) was isolated from the lipophilic extract of a collection of the benthic marine cyanobacterium Caldora sp. from reefs near Fort Lauderdale, Florida. The planar structure of this new compound was determined by spectroscopic methods and comparisons between HRMS and NMR data with its reported methyl ester. The absolute configuration of the single chiral center was determined by the conversion of 1 to the methyl ester and the comparison of its specific rotation data with the two known methyl ester isomers, 2 and 3. Molecular sequencing with 16S rDNA indicated that this cyanobacterium differs from Caldora penicillata (Oscillatoriales) and represents a previously undocumented and novel Caldora species. Dysidazirine (2) showed weak cytotoxicity against HCT116 colorectal cancer cells (IC₅₀ 9.1 µM), while dysidazirine carboxylic acid (1) was non-cytotoxic. Similar cell viability patterns were observed in RAW264.7 cells with dysidazirine only (2), displaying cytotoxicity at the highest concentration tested (50 µM). The non-cytotoxic dysidazirine carboxylic acid (1) demonstrated anti-inflammatory activity in RAW264.7 cells stimulated with LPS. After 24 h, 1 inhibited the production of NO by almost 50% at 50 µM, without inducing cytotoxicity. Compound 1 rapidly decreased gene expression of the pro-inflammatory gene iNOS after 3 h post-LPS treatment and in a dose-dependent manner (IC₅₀ ~1 µM); the downregulation of iNOS persisted at least until 12 h.     

A single microcystin in a toxic Microcystis bloom from the river Río de la Plata (Argentina)

Microcystis is one of the most common bloom-forming cyanobacteria genera in diverse ecosystems. More than 80% of its strains are toxic, mainly due to their ability to produce metabolites known as microcystins (MC). Here we report on a M. aeruginosa bloom that appeared in the summer of 2001 at a site of the Río de la Plata, within the city of Buenos Aires. The symptoms in mice indicated that the bloom was hepatotoxic. LC-PDA analysis revealed a similar high concentration (0.9–1?mg?g^–1?d w) of just one MC in the bloom biomass during the 3-month study period. During this period most of the MC (ca. 98 %) was found intracellularly, and the content remained almost the same. The molecular mass of the bloom MC was 1036?Da, as deduced from LC-ESI-MS data. Fragment ion analysis by LC-IT-MS-MS allowed identifying 6 out of the 7 amino acids, as well as their position in the molecule. The molecular mass of the unidentified amino acid residue was 155?Da. According to the data obtained, the MC under study was MC-XR, X representing the unidentified amino acid. This is the first report both on the characterisation of MCs in an urban site of the Río de la Plata waters, and on an Argentinean bloom exhibiting only one MC variant.     

Nanoparticulate materials and regulatory policy in Europe: An analysis of stakeholder perspectives

The novel properties of nanoparticulate materials (NPM) and the rapid development of NPM based products have raised many unanswered questions and concerns by different stakeholders over its consequences for the environment and human health. These concerns have led to an increasing discussion in both the US and Europe about possible regulatory policies for NPM. In this article a comparative study of stakeholders’ perceptions on regulatory policy issues with NPM in Europe is presented. It was found that industry wants to regulate this area if the scientific evidence demonstrates that NPM are harmful, but also that the regulatory bodies do not find it necessary at this point of time to regulate until scientific evidence demonstrates that NPM are harmful. This research therefore shows that there will most likely not be any regulatory interventions until there is an established and convincing scientific knowledge base demonstrating that NPM can be hazardous. It is furthermore discussed in this article the different roles and responsibilities of the stakeholders in financing the research required to establish the necessary level of fundamental scientific evidence. It was also found that the activity of the regulatory bodies on this issue differ between the European countries.     

基于自动磁珠转运的转基因蛋白Cry1Ab检测

基于自动磁珠转运,建立了转基因蛋白Cry1Ab免疫检测的新方法.利用水热法制备了粒径约400 nm的纳米磁球,并进行电镜表征,通过溶胶法对磁球表面进行氨基修饰,采用戊二醛偶联对磁珠实现抗体包被,在核酸提取仪中进行酶联免疫反应,采用分光光度法进行检测.本方法对转基因蛋白Cry1Ab的检出限低于1 μg/L,与商品化酶联免...     

Fungal upgrading of wheat straw for straw-thermoplastics production

Combining biologic pretreatment with storage is an innovative approach for improving feedstock characteristics and cost, but the magnitude of responses of such systems to upsets is unknown. Unsterile wheat straw stems were upgraded for 12 wk with Pleurotus ostreatus at constant temperature to estimate the variation in final compositions with variations in initial moisture and inoculum. Degradation rates and conversions increased with both moisture and inoculum. A regression analysis indicated that system performance was quite stable with respect to inoculum and moisture content after 6 wk of treatment. Scale-up by 150× indicated that system stability and final straw composition are sensitive to inoculum source, history, and inoculation method. Comparative testing of straw-thermoplastic composites produced from upgraded stems is under way.     

控藻鲢鱼的捕捞策略

鲢鱼是一种以水中浮游动植物为食的滤食性鱼类,利用鲢鱼控制蓝藻数量是一种有效的纯生物手段.分析蠡湖鲢鱼资源稳定的条件,建立鱼量的基本方程式及利润模型,给出利润与捕捞强度的关系和鱼群数量的变化趋势.最后得到了鲢鱼的放流与回捕策略.