实时荧光定量PCR技术研究进展及应用

实时荧光定量PCR(Real-time fluorescent quantitative polymerase chain reaction,Real-time PCR)技术是20世纪90年代中期发展起来的一种新型核酸定量技术.它利用荧光实时检测PCR反应,具有灵敏度高、特异性强、节约时间等优点.文章就常用的4种方法,即DNA结合染色、水解探针、分子信标和杂交探针的原理和特点进行介绍,同时综述了荧光定量PCR技术在实践中的应用.     

高寒阴湿地区半开放型暖棚牛舍冬季内环境监测评价

在高寒阴湿的寒冷地区修建半开放型暖棚牛舍,充分利用塑料膜的温室效应,能够达到保暖增膘的饲养目的,本课题研究采用定期定点观测的方法,在冬春季扣膜后,对暖棚牛舍和普通圈舍的采光系数、入射角、透光角、舍内外的温度、湿度及CO2、NH3、H2S等主要技术指标进行了监测和对比.结果表明暖棚牛舍(试验组)舍内11月份～3月份平均温度为8.78℃;平均湿度为55.53%;舍内的CO2含量平均为0.141%;NH3平均为19.02 mg/m3;H2S平均为9.91 mg/m3;采光系数为0.86;入射角为64°;透光角为45°.普通牛舍(对照组)的平均温度为0.25℃;平均湿度为66.75%;舍内的CO2平均为0.137%;NH3平均为18.49 mg/m3;H2S平均为9.64 mg/m3;采光系数为0.082;入射角为35°;透光角为10°.试验组牛的授配率、产仔成活率、繁活率分别比对照组提高了24%、17%、50%,而患病率降低了2.6%.     

Monitoring the Immune Status of Broilers Against Reoviruses Using Challenge and Serologic Data

Reoviruses are an important cause of suboptimum performance in commercial broilers worldwide. Integrators use the enzyme-linked immunosorbent assay against the S1133 antigen for monitoring serum of breeders for indicating pullet vaccine success. However, without correlating serology to reovirus challenge, it is difficult to determine whether titers reflect protective immunity. We developed a broiler challenge test against 2 common reovirus isolates (2408 and S1133) to evaluate the efficacy of reovirus pullet vaccine programs. Two reovirus serologic and challenge studies were undertaken using chicks from broiler integrators from the southeastern United States. Breeder flocks, from which the chicks were obtained, received at least 1 live and 2 inactivated reovirus vaccines during their pullet phase. One-day-old progeny were collected from 6 breeder flocks. At 1 d of age, 20 chicks from each broiler flock were bled, and serum was analyzed for antibodies. At 3 to 4 d of age, 20 progeny per flock were challenged with the 2408 reovirus by intratracheal route. At 10 to 14 d of age, another 20 birds per flock were challenged with the S1133 reovirus by footpad. Twenty birds per flock were used as nonchallenged controls. At 3 wk of age, all birds were killed and weighed. Percentage of protection was calculated for each flock based on the absence of gross lesions. Flocks with at least 50% protection were considered well protected. Most flocks were well protected against both viruses. The percentage of protection correlated with day-old enzyme-linked immunosorbent assay titers. Chicks from younger hens had higher titers and the best protection against challenge. Producers, whose hen flocks were monitored herein, were doing a good job of immunizing pullets against reovirus. They are now using reovirus progeny challenge studies along with breeder antibody titers to determine vaccination success of their pullets.     

Landscape improvement, or ongoing degradation – reconciling apparent contradictions from the arid rangelands of Western Australia

Recent quantitative site-based monitoring and qualitative aerial and ground traverses provide contrasting assessments of the health of much of the arid shrublands of Western Australia extensively grazed by livestock (‘rangelands’). Although these results seem incompatible, we explain the apparent contradictions based on landscape succession processes operating at multiple levels of ecological organisation. Specifically, we suggest that the intact areas in which site-based monitoring is conducted are contracting as catchment canalisation and desiccation increase. However, the impacts of these processes have not yet become manifest at the site scale. The site-based system addresses important regional questions. These relate to the large, relatively intact areas away from most active surface flows, which should be a focus for resource conservation, given practical limits to repairing widespread degradation with low management inputs. We provide a complementary set of questions to provide a more comprehensive audit of rangeland dynamics in the context of underlying hierarchical landscape patterns and processes that might threaten intact areas. We recognise the need to match questions and levels of ecological organisation and the implications these have for sampling. We also recognise the difficulty in producing concise statements of change for clients when reporting on complex ecological issues and processes. Without a clearly articulated, and well understood, hierarchical model of pattern and process within which apparently contradictory findings can be reported meaningfully, policy makers may be confused by the results, with the consequent risk of policy inaction.     

Assessment of real-time PCR as a method for determining the presence of <Emphasis Type="Italic">Verticillium dahliae</Emphasis> in different Solanaceae cultivars

Real-time PCR was used to detect and quantify Verticillium dahliae and to assess the susceptibility of four Capsicum annuum cultivars (Luesia, Padrón, SCM331 and PI201234) and the Capsicum chinense cv. C118 to this pathogen. The symptoms which developed after infection included stunting and yellowing, and were more acute in the cv. SCM331, which also suffered defoliation in later stages of the disease and in C118, which suffered severe stunting. Quantification of the pathogen DNA in roots 23 and 34 days post-inoculation (dpi) revealed that there were significantly higher amounts of Verticillium dahliae DNA in C118 than in the other cultivars, followed by SCM331, Padrón and PI201234. The lowest amounts of fungal DNA in roots were found in Luesia. In hypocotyls, the highest amounts of fungal DNA were found in SCM331, while Luesia, Padrón and PI201234 had much lower amounts, and C118 had intermediate levels. When a compatible versus an incompatible system was studied, using the near-isogenic tomato lines LA3030 (susceptible) and LA3038 (resistant to V. dahliae), we were able to detect fungal DNA in both lines. As expected, the fungus/plant DNA ratio was lower in LA3038 than in LA3030 and it decreased with time in LA3038. The amount of Verticillium dahliae DNA in the roots of LA3030 remained constant between days 23 and 34 post-inoculation, but increased 10-fold in collars. Finally, when real-time PCR was applied as a diagnostic method to samples from pepper plants, soil and water collected from farms in northwest Spain, we were able to detect V. dahliae DNA in these samples even when symptoms of the disease were not evident.     

A Simple Apparatus for Frequent Measurement of Gastrointestinal Intraluminal PCO2

The accuracy and precision of an end-tidal infrared CO₂ monitor and customized capnography tubing system designed to measure gastrointestinal intraluminal CO₂ partial pressure (P_iCO₂) were tested in vitro. Samples were taken from the customized capnography tubing placed in either 5% or 10% CO₂ gas at discrete intervals ranging from one minute to twelve minutes. For a given time interval, the tubing PCO₂ measurement was a constant fraction of the actual PCO₂ (all standard errors < 0.02). For increasing time intervals, the ratio of the tubing PCO₂ to actual PCO₂ increased logarithmically. In the 5% and 10% CO₂, the regression coefficients were 0.89 and 0.85 for 8 French tubing and 0.99 and 0.91 for 6 French tubing. Beacuase of its accuracy and precision, this system may provide automated gastrointestinal CO₂ partial pressure monitoring at short intervals (e.g. 5 minutes), facilitating testing of the role of gastrointestinal P_iCO₂ information in treatment algorithms. (Vet Emerg & Crit Care, 1998; 8: 109–116)     

基于ZigBee无线网络的大棚种植温度监测系统

针对大棚种植温度监测系统,讨论了无线温度监测系统的技术要求,阐述了基于ZigBee无线检测网络的系统结构与硬件、软件设计。随着规模农业的快速发展,无线网络农业自动化系统将有非常广阔的推广应用前景。     

农药产品中添加未经登记成分的调查与分析

通过连续6年的福建省农药市场监测,对擅自添加未经登记农药成分的278份样品进行统计分析,研究表明:被添加农药的产品主要为杀虫剂,剂型主要为乳油、可湿性粉剂,多登记在蔬菜、果树、茶树、水稻、棉花上;添加的农药品种主要为有机磷类和拟除虫菊酯类杀虫剂,其防治对象与原产品相比有的属于防治谱相同,有的属于扩大杀虫谱。同时指出该行为的危害性,提出加强监管、出台检测标准和判定标准的建议。     

Effects of the 1995–1997 drought on nitrate leaching in lowland England

Abstract. The effect of drought between summer 1995 and 1997 on stream and river nitrate concentrations was investigated using sites close to the long-running meteorological station in Oxford, UK. Nitrate concentrations in the River Windrush were relatively low during the drought, but after it had ended reached the highest level since records began in 1973. The low concentrations during the drought probably reflect a reduced contribution from agricultural runoff. High nitrate concentrations were found in a field drain at Wytham Environmental Change Network site during and after the drought, but discharge was greatly reduced. A woodland stream at Wytham had much lower nitrate concentrations than the field drain but these similarly increased during and after the drought. There was evidence that both a concentrating effect of low water volumes and enhanced soil nitrogen mineralization and nitrification rates were causing concentrations to rise. The effects of mineralization and nitrification were more important in woodland than agricultural land. Nitrate load over the course of a year was determined largely by discharge, but steeper gradients for the relationship between cumulative load and cumulative discharge were seen during and after the drought than before, reflecting the higher concentrations.     

Watershed Health Characterization Using Reliability–Resilience–Vulnerability Conceptual Framework Based on Hydrological Responses

An attempt was made to employ the reliability (R_el)–resilience (R_es)–vulnerability (V_ul) conceptual framework to develop a typical indicator system for quantitative assessment of watershed health. The study aimed to conceptualize and customize the R_elR_esV_ul framework to watershed health assessment for the Shazand Watershed in Markazi Province, Iran, for the period of 1977–2014. To this end, four easily, reliable, available and accessible criteria viz. standardized precipitation index (SPI), low and high flow discharges (LFD and HFD), and suspended sediment concentration (SSC) were selected, and corresponding indices for reliability–resilience–vulnerability (R_elR_esV_ul) framework were accordingly conceptualized and calculated. The thresholds of 0.1, 0.16 m³ s⁻¹, 12.63 m³ s⁻¹ and 25 mg l⁻¹ day⁻¹ were thus selected for SPI, LFD, HFD and SSC, respectively. The results showed a decreasing trend in R_el and R_es, and an increasing trend in V_ul for SPI and LFD in the Shazand Watershed. The results further showed an increasing trend in R_el, and a decreasing trend in V_ul for HFD and SSC. A decreasing trend was ultimately recognized in watershed health index for all criteria except SSC. Additionally, the integrated hydrological watershed health index of 0.16 ± 0.11 obtained from the geometric mean of the R_elR_esV_ul framework indices also showed a decreasing trend for the Shazand Watershed health during the study period. The results of the present initiative study can be considered as a baseline by decision makers and managers to effectively adjust watershed management strategies to handle land degradation issues in the area. Copyright © 2016 John Wiley & Sons, Ltd.