马铃薯晚疫病(Phytophthora infestans (Mont.) de Bary)的流行和防治研究

1997年做了田间试验用来评价影响马铃薯晚疫病流行的关键天气条件.在Reckenholz做了2个试验研究晚疫病的潜伏期和侵染速率.结果表明,当累计有效积温达到2346.5℃·h时,孢子囊开始在马铃薯叶片出现.温度是影响晚疫病流行的重要因子.病害侵染的重要条件是温度超过10℃并且在连续6h内空气相对湿度大于90%.降雨在病害传播中发挥了重要作用.根据PhytoPRE和CWC两个决策支持系统所采取的病害防治取得了较好的病害防治效果.     

鼻咽癌来源LMP1转基因小鼠的制备

本试验利用显微注射技术，制备鼻咽癌来源LMP1基因（N-LMP1）的转基因小鼠。共获得15只首建鼠，经小鼠尾部组织DNA分析，PCR法证明其中两只小鼠有N-LMP1基因扩增带，Southern杂交显示PCR阳性小鼠有特异的杂交信号，整合率为13.3%，N-LMP1转基因小鼠的建立为研究N-LMP1转基因小鼠的建立为研究N-LMP1在鼻咽癌变过程中的作用机制奠定了基础。     

Evaluation of an experimental Aeromonas salmonicida epidemic in chinook salmon, Oncorhynchus tshawytscha (Walbaum)

To determine the dynamics of the transmission of Aeromonas salmonicida ssp. salmonicida infection, chinook salmon, Oncorhynchus tshawytscha, were exposed to bacteria by cohabitation. The latent period (time between exposure and infectivity) was determined by exposing a group of chinook salmonid fingerlings to A. salmonicida by bath, then, at daily intervals, by holding five exposed (donor) fish with approximately 50 naive fish for 24 h. The latent period was 3 days post-infection and the time period between the initial exposure to bacteria and the beginning of bacterial shedding was 4.5 days for the same animals. The prevalence and intensity of infection in the donor fish, to which recipient fish were exposed, i.e. the level of exposure, was highly correlated with the development of disease in recipient (susceptible) chinook salmon (r2 = 0.57). An experiment was conducted to determine the daily progress of infection and development of a furunculosis epidemic among recipient fish by cohabiting a single exposed fish with 43 unexposed salmon. At daily intervals, all fish (in seven treatment tanks and one control tank daily) were sacrificed and tested for the presence of A. salmonicida in the kidney (n = 3520). Over 10 days, mean prevalence among recipient fish reached 75% and disease related mortality exceeded 50%. Bacterial concentrations in the water continued to increase over the duration of the experiment in concert with the number of infected animals present in the population.     

Comparative spatial analysis of the sooty blotch/flyspeck disease complex,bull’s eye and bitter rots of apples

The incidence of sooty blotch/flyspeck (SBFS) and bitter and bull’s eye rots were assessed in a Fuji apple orchard during two seasons. Using a regular sampling design, 252 trees were selected and 20 fruits per tree were sampled at harvest and scored for disease incidence. For bitter and bull’s eye rots, additional assessments were made on all symptomless fruit after a 30‐day period of storage. Randomness in the spatial pattern was assessed using beta‐binomial analysis of incidence data for three sampling scales (one, three or six adjacent trees as sampling units) and using Spatial Analysis by Distance Indices (sadie ) for disease counts for the 3‐tree sampling scale. sadie was also used for testing spatial associations between a pair of diseases, between years for the same disease or between rotted and latently infected fruit. Using a toroidal‐shifts procedure, 360 maps of disease counts were created based on the observed data, which were further analysed using sadie . Most datasets showed an aggregated spatial pattern, which was more consistent for the two fruit rots than SBFS, which showed distinct patterns depending on the year or method of analysis. The two fruit rots were spatially associated in most situations but SBFS and bull’s eye rot were dissociated in one season. Results from virtual orchards showed that the patterns observed in the original maps may accurately represent those in similar apple‐growing areas. Hypotheses regarding aspects of ecology and epidemiology of pathogens studied and potential efficacy of control measures in the region are discussed.     

基于K-OPLS的无线传感网络室内定位跟踪算法

针对基于指纹的无线传感网络室内定位,提出了一种基于核隐变量正交投影(Kernel-based orthogonal projection to latent structures,K-OPLS)的定位算法。在O-PLS的模型框架下,K-OPLS算法应用"核技巧"将描述变量映射至高维特征空间,给出了描述变量和响应变量之间的非线性关系,以实现对模型的预测成分及与响应-正交成分的计算。K-OPLS算法集核偏最小二乘建模和正交信号校正预处理方法于一体,在一定程度上有效地改进了模型性能,增强了模型解释性。基于RSSI指纹信息,构建锚节点与处于参考位置的非锚节点之间的非线性映射关系,K-OPLS算法可以实现WSN的室内定位跟踪。将所提出的算法应用于仿真与物理环境下的不同实例中,在同等条件下,还与核岭回归(KRR)、核极限学习机(KELM)、核信噪比(KSNR)、核偏最小二乘(KPLS)、核自适应滤波等其他核学习算法进行比较。仿真实验中,基于小波核的WK-OPLS算法在无噪声和有噪声环境下的跟踪估计误差分别为0. 232 6、1. 320 5 m。物理实验中,基于小波核的该算法跟踪估计误差为0. 249 3 m。实验结果表明,所提算法有效提高了定位精度,而且具有一定的除噪能力。     

Temporal and spatial field evaluations highlight the importance of the presymptomatic phase in supporting strong partial resistance in Triticum aestivum against Zymoseptoria tritici

Zymoseptoria tritici, the causal agent of septoria tritici blotch (STB), remains a significant threat to European wheat production with the continuous emergence of fungicide resistance in Z. tritici strains eroding the economic sustainability of wheat production systems. The life cycle of Z. tritici is characterized by a presymptomatic phase (latent period, LP) after which the pathogen switches to an aggressive necrotrophic stage, when lesions bearing pycnidia quickly manifest on the leaf. As minimal knowledge of the possible role of the LP in supporting STB resistance/susceptibility exists, the goal of this study was to investigate the spatial and temporal association between the LP and disease progression across three locations (Ireland – Waterford, Carlow; UK – Norwich) that represent commercially high, medium and low STB pressure environments. Completed over two seasons (2013–2015) with commercially grown cultivars, the potential of the LP in stalling STB epidemics was significant as identified with cv. Stigg, whose high level of partial resistance was characterized by a lengthened LP (c. 36 days) under the high disease pressure environment of Waterford. However, once the LP concluded it was followed by a rate of disease progression in cv. Stigg that was comparable to that observed in the more susceptible commercial varieties. Complementary analysis, via logistic modelling of intensive disease assessments made at Carlow and Waterford in 2015, further highlighted the value of a lengthened LP in supporting strong partial resistance against STB disease of wheat.     

我国北方部分苹果主产区病毒病的发生与检测

苹果病毒病在我国广泛发生,已成为限制我国苹果优质高产的关键因素。20世纪80年代曾对其做过详细的调查和研究,但近年来由于各地农业产业结构调整等因素,苹果病毒病的发生特点有了不同程度的变化。为了解目前我国苹果病毒病的发生情况,在我国北方苹果主产区山东、陕西、山西、辽宁、北京和黑龙江6个省市的部分地区采集苹果样品共计267份,经RT-PCR检测和扩增产物的克隆与测序分析表明在上述地区采集的样品中,苹果褪绿叶斑病毒(ACLSV)、苹果茎沟病毒(ASGV)、苹果茎痘病毒(ASPV)、苹果锈果类病毒(ASSVd)的发生率分别为66.7%~100.0%、38.1%~94.1%、4.8%~85.7%和4.8%~48.6%;苹果凹果类病毒(ADFVd)仅在山东的两个果园零星发生;6个省市样品中病毒复合侵染率分别为67.1%、92.1%、75.0%、88.2%、94.1%和76.2%。