基于电子鼻的花生有害霉菌种类识别及侵染程度定量检测

针对花生霉变传统分析方法操作繁琐、时效性差等不足,该研究拟利用电子鼻气体传感技术建立起花生有害霉菌污染的快速检测方法。辐射灭菌花生籽粒分别接种5种谷物中常见有害霉菌(黄曲霉3.17、黄曲霉3.395 0、寄生曲霉3.395、寄生曲霉3.012 4和赭曲霉3.648 6),并于26℃、80%相对湿度条件下储藏9 d至严重霉变。利用电子鼻气体传感器获取不同储藏时期(0、3、6、9 d)花生样品的整体挥发性气味信息。最后,结合多元统计分析方法对电子鼻传感器响应信号进行特征提取,建立了花生中有害霉菌污染程度的定性定量分析模型。结果显示,主成分分析法(principal component analysis,PCA)可成功区分不同霉菌侵染程度的花生样品,线性判别分析(linear discriminant analysis,LDA)模型对样品不同储藏天数判别的准确率均达到或接近100%。花生中菌落总数的偏最小二乘回归分析(partial least squares regression,PLSR)模型的预测决定系数和预测相对均方根误差分别达到0.814 5和0.244 0 lg(CFU/g)。结果表明,应用电子鼻技术快速检测储藏期间花生霉变状况具有一定可行性,可为利用气味信息实现粮食霉菌污染的在线监测提供理论参考。     

利用QuantStudioTM 3D数字PCR分析转基因玉米MON863含量

QuantStudioTM 3D数字PCR (QuantStudioTM 3D digital PCR,3D-dPCR)是一种基于超高密度亲疏水微孔芯片实现数字PCR分液原理的新型核酸绝对定量平台,在转基因生物定量领域具有极大的应用前景.本研究基于3D-dPCR平台,以转基因玉米(Zea mays)MON863混合样品为例,建立基于单重和双重数字PCR体系的转基因生物(genetically modified organisms,GMOs)含量分析方法.与传统qRT-PCR比较发现,在缺乏样品纯度、纯合度信息的情况下,数字PCR能够较好地排除这些因素的影响,测定准确的量值.研究结果表明,QuantStudioTM 3D数字PCR是一种适用于转基因生物含量分析的精确定量方法,还可反映转基因玉米种子的基因型.本研究基于3D-dPCR建立的转基因玉米MON863单重和双重定量方法为转基因检测提供了新的方法和参考.     

Populations, Community Composition and Biomass of Aquatic Organisms in the Floodwater of Rice Fields and Effects of Field Management

As rice fields are managed for improved rice production, many studies on aquatic organisms in the floodwater have been restricted to agronomically important members such as blue-green algae (BGA) and Azolla , and ecological studies on common aquatic organisms were relatively limited to specific group members. In the present paper, studies on all the aquatic organisms in the floodwater, from protozoa to insects and fishes, were reviewed worldwide from the viewpoint of rice field ecology, paying attention to their populations, seasonal variations, antagonistic relations and biomass, and the effect of field management. Most studies conducted in India and in the Southeast Asian countries dealt with the BGA and green algal populations. In contrast, protozoa and aquatic animals were extensively studied in rice fields in Europe. Japanese studies in the past were intermediate between the previously cited studies. They generally described specific groups depending on the authors' interests, and surprisingly few studies dealt with the community level and prey-predator relationships. Field management such as fertilizer and pesticide application, water management and plowing was found to play a major role in determining the populations of aquatic organisms. Overview of research on aquatic organisms in the floodwater of rice fields suggests several directions for future studies.     

Arbuscular mycorrhizal fungi are directly and indirectly affected by glyphosate application

Glyphosate is a systemic non-selective herbicide, the most widely used in the world. Alongside with its use in agricultural and forestry systems, this herbicide is used in grasslands in late summer with the aim of promoting winter species with the consequent increase in stocking rate. However, its effects on non-target organisms, such as arbuscular mycorrhizal fungi (AMF), are unclear. Arbuscular mycorrhizal fungi (AMF) colonize the root of more than 80% of terrestrial plants, improving their growth and survival, and therefore playing a key role in ecosystem structure and function. The aim of this work was to investigate the possible pathways through which glyphosate application affects AMF spores viability and root colonization in grassland communities. Our hypothesis is that glyphosate application can damage AMF directly (through contact with spores and external hyphae) or indirectly through the changes it generates on host plants. The experiment had a factorial array with three factors: (1) plant species, at two levels (Paspalum dilatatum and Lotus tenuis), (2) doses of glyphosate, at three levels (0 l ha⁻¹, 0.8 l ha⁻¹ and 3 l ha ⁻¹), and (3) application site, at two levels: soil (direct pathway) and plant foliage (indirect pathway). Spore viability was reduced even under the lowest glyphosate rate, but only when it was applied on the soil. Total root colonization for both species was similarly decreased when glyphosate was applied to plant foliage or on soil, with no difference between 0.8 and 3 l ha⁻¹. The number of arbuscules was 20% lower when glyphosate was applied on plant foliage, than when it was applied on the soil. Our findings illustrate that glyphosate application negatively affects AMF functionality in grasslands, due to different causes depending on the herbicide application site. While, under field conditions, the occurrence of direct and/or indirect pathways will depend on the plant cover at the time of glyphosate application, the consequences of this practice on the plant community structure will vary with the mycorrhizal dependence of the species composition regardless of the pathway involved.     

山西省转BT基因棉田害虫发生规律研究

通过对转BT基因棉田及常规棉田害虫的对比调查研究,并结合室内饲养,明确了山西省转BT基因棉田害虫的主要种类及其与常规棉田害虫发生规律的不同点,为新的生态条件下山西省棉田害虫综合治理提供了依据。     

Functional and numerical responses of Cyrtorhinus lividipennis to eggs of Nilaparvata lugens are not affected by genetically modified herbicide-tolerant rice

To safely and sustainably utilize genetic breeding techniques for crop production, greater understanding of the potential effects of genetically modified herbicide-tolerant (GMHT) crops on the ecological functions of predators is required. In the laboratory, we examined the functional and numerical responses of Cyrtorhinus lividipennis Reuter to eggs of brown planthopper (BPH), Nilaparvata lugens (Stål), which were reared on GMHT rice Bar68-1; the untransformed parental cultivar, D68; or a BPH-susceptive rice variety, Taichung Native 1. All stages of nymphs and female adult of C. lividipennis, either on GMHT rice or control plants, exhibited typical type II functional responses when fed on BPH eggs; the attacking rate and handling time of C. lividipennis on GMHT rice Bar68-1 was not significantly different from that on D68. The numerical responses of C. lividipennis on GMHT rice or controls fit Beddington’s model; there were no significant differences in the parameters of numerical responses between GMHT rice Bar68-1 and D68. The results indicated that the functional and numerical responses of C. lividipennis to BPH eggs are not affected by GMHT rice Bar68-1.     

小麦黑胚病菌及其分离方法比较

河南省小麦黑胚菌主要是交链孢菌[包括细交链孢菌（Alternaria tenuis)与极细交链孢菌（A.tenuissima)]和麦类根腐德氏霉菌（Drechslera sorokimiana)。检验小麦黑胚病菌以组织分离法最为准确,以清水培养法较为简捷。     

Bottom-up down from the top: Honeydew as a carbon source for soil organisms

Honeydew produced by aphids is a well-studied food source for mutualistic ants. Although considerable amounts drop onto the soil surface there are hardly any studies dealing with the potential effects of this additional C source for soil organisms, particularly those living at the soil surface. We studied this question by simulating honeydew and investigating plots under Populus canescens formerly infested with aphids on two ruderal sites differing in soil organic matter content and vegetation cover. The simulated honeydew input increased microbial biomass with some delay in week 10. Both natural and simulated honeydew raised the activity densities of an epigeic Collembola taxon, the Bourletiellidae, but not of the dominant Hemisotoma thermophila. The honeydew effect varied over time and with the site, and was more pronounced at the nutrient-poor site for Collembola, but not for microbial biomass. Ant consumption reduced the amount of honeydew reaching the soil surface by 50%. The activity density of H. thermophila was negatively related to ants and spiders, hinting at a top-down control. Honeydew clearly acts as a bottom-up force for soil organisms, which is however only part of the complex network connecting the food webs of primary producers and decomposers.     

肉制品加工过程中的有毒有害成分分析

从我国食品安全现状的分析入手,着重关注我国肉制品的安全发展现状及其加工生产过程中有毒有害物质。通过查阅相关资料研究发现:随着肉制品生产工艺和技术的不断发展,使得肉制品质量安全存在一定的隐患,肉制品中有毒有害物质以苯并(a)芘为代表。对肉制品中的有毒有害物质检测方法的分析对比得出:采用高效液相色谱检测苯并(a)芘,具有灵敏度高、分析时间短、分离效率高等优点。     

食品用塑料包装中有害物质迁移研究进展

食品用塑料包装中有害物质迁移问题已成为食品安全的重要隐患。介绍食品用塑料包装中存在的主要有害物质种类,对有害物质向食品或食品模拟物中迁移研究的现状进行总结,并就如何提高该问题的监督管理水平提出建议。