Detection and molecular characterization of sugarcane grassy shoot phytoplasma in Vietnam

Sugarcane is an important cash crop in Vietnam and has been widely promoted at national and provincial level. In 2006, a new disease was discovered in sugarcane in the Nghean Tate&Lyle Sugar Mill in Nghean Province in north-central Vietnam. The key symptoms were the formation of green grassy shoots around the base of mature stools. We applied nested polymerase chain reaction (PCR) using P1/P7 and R16F2n/R16R2 for detection and characterization of phytoplasma from the symptomatic tissues. PCR products of the expected size (approx. 1200?bp) were obtained from the 16S rDNA of the phytoplasma. The restriction fragment length polymorphism profiles indicated that all samples were infected by the same phytoplasma. Phylogenetic analysis confirmed that the SCGS phytoplasma from Vietnam belong to the 16SrXI group, formerly Rice Yellow Dwarf group.     

Effect of postactivation treatment with latrunculin a on in vitro and in vivo development of cloned embryos derived from kidney fibroblasts of an aged clawn miniature boar

The objective of this study was to examine the effect of postactivation treatment with latrunculin A (LatA), an actin polymerization inhibitor, on in vitro and in vivo development of somatic cell nuclear transfer (SCNT) embryos derived from kidney fibroblasts of an aged Clawn miniature boar (12 years old). After electric activation, SCNT embryos were treated with 0, 0.5 or 1 μM LatA and cultured in vitro. The rate of blastocyst formation was significantly higher (P<0.05) in SCNT embryos treated with 0.5 μM LatA (38%) than those in control (14%). When cloned embryos treated with 0.5 μM LatA were transferred into the oviducts of two recipient miniature gilts to assess their development in vivo, both recipients became pregnant; one maintained pregnancy to term, and a live piglet (weighing 220 g) was delivered by Caesarean section. The results of this study indicated that the postactivation treatment with LatA was effective in improving in vitro developmental capacity of SCNT miniature pig embryos derived from kidney fibroblasts of an aged animal and that miniature pig cloned embryos treated with LatA had the ability to develop to term.     

武汉地区三角梅遮光催花试验研究

本试验以1～3 a生的三角梅盆花为试材,以遮光处理为研究手段进行武汉地区三角梅花期调控试验探索,结果表明:在20～30℃的温度条件下,用栽培地布对三角梅进行连续遮光处理20 d,能完成稳定的花芽分化,继续遮光25 d可开花,并在此期间将腐熟的有机肥上清液稀释10倍灌根代替浇水能有效促进三角梅开花。     

基于注意力机制神经网络的荒漠区蒸散量模拟

该研究对基于注意力机制的长短期记忆（Attention-Based Long Short Term Memory，AT-LSTM）模型对蒸散量（Evapotranspiration，ET）模拟的可行性和有效性进行验证，以提高环境数据缺失情况下的蒸散量模拟精度。基于盐池县2012-2017年的每30 min环境数据，利用不同环境因子组合构建基于注意力机制的LSTM模型，并将其与极限学习机（Extreme Learning Machine，ELM）模型、支持向量机（Support Vector Machine，SVM）模型、长短期记忆（Long Short Term Memory，LSTM）模型在日尺度、月尺度和季节尺度上进行对比分析。结果表明：与其他3种模型相比，当输入环境因子变化时，AT-LSTM模型模拟精度变化很小，模拟效果均较好。当输入空气温度、净辐射、相对湿度、土壤温度、土壤含水率所有环境因子时，基于AT-LSTM模型的模拟效果最好，均方根误差（Root Mean Square Error，RMSE）为0.013 mm/30 min，平均绝对误差（Mean Absolute Error，MAE）为0.006 mm/30 min，相关系数（Correlation Coefficient，R）值为0.905。且无论是从小时尺度、日尺度和月尺度来看，AT-LSTM模型的模拟效果均优于其他3种模型。在环境因子缺失的情况下，净辐射对盐池县ET的模拟贡献程度最大，仅输入净辐射时，AT-LSTM模型模拟得到的RMSE和MAE分别为0.014、0.007 mm/30 min，R为0.892，模型模拟精度较高，AT-LSTM模型模拟精度高，模型稳定性强，对蒸散量模拟预测具有一定的适用性，仅输入净辐射的AT-LSTM模型可以作为环境数据缺失条件下的蒸散量预测模型。     

浅谈中国园林中的水榭

通过若干实例分析,探讨了中国园林中水榭的形式风格以及在园林中的功能。     

Solid-Phase Extraction Embedded Dialysis (SPEED), an Innovative Procedure for the Investigation of Microbial Specialized Metabolites

Solid-phase extraction embedded dialysis (SPEED technology) is an innovative procedure developed to physically separate in-situ, during the cultivation, the mycelium of filament forming microorganisms, such as actinomycetes and fungi, and the XAD-16 resin used to trap the secreted specialized metabolites. SPEED consists of an external nylon cloth and an internal dialysis tube containing the XAD resin. The dialysis barrier selects the molecular weight of the trapped compounds, and prevents the aggregation of biomass or macromolecules on the XAD beads. The external nylon promotes the formation of a microbial biofilm, making SPEED a biofilm supported cultivation process. SPEED technology was applied to the marine Streptomyces albidoflavus 19-S21, isolated from a core of a submerged Kopara sampled at 20 m from the border of a saltwater pond. The chemical space of this strain was investigated effectively using a dereplication strategy based on molecular networking and in-depth chemical analysis. The results highlight the impact of culture support on the molecular profile of Streptomyces albidoflavus 19-S21 secondary metabolites.     

利用手工克隆技术培育体细胞克隆莱芜猪

为探讨手工克隆技术在克隆中国地方猪种的可行性,本研究组利用手工克隆技术平台,以中国地方猪品种莱芜猪的耳皮肤细胞作为核移植的供体细胞,以体外成熟的猪卵母细胞为受体细胞,进行体细胞克隆猪培养,成功培育了25头克隆莱芜猪。表明手工克隆技术可应用于莱芜猪体细胞克隆,为莱芜猪的保种及育种提供了新的途径。     

Prevalence of bovine genital campylobacteriosis and trichomonosis of bulls in northern Nigeria

Background

A survey was conducted to determine the prevalence of campylobacteriosis and trichomonosis, and their concurrence with brucellosis, in cattle in three states of northern Nigeria.

Methods

A total of 602 preputial samples was collected from bulls in 250 herds and tested using culture and identification. Various indigenous and exotic breeds were studied and four major management systems were encountered. Age of the cattle was estimated using dentition, farm records or cornual rings.

Results

The estimated true animal-level prevalence of Campylobacter fetus infection was 16.4% (95% CI: 13.0-20.7), of which 18.5% was C. f. fetus and 81.5% was C. f. venerealis. Of the latter, 92% were C. f. venerealis biovar intermedius strains. Animal-level prevalences in Adamawa, Kano and Kaduna states were 31.8%, 11.6% and 8.3% respectively, and were highest in bulls >7 years old (33.4%) and in the Gudali breed (28.8%). Of the 250 herds, 78 (25.5%, 95% CI: 19.4-32.7) had at least one infected bull, and herd prevalence was highest in the pastoral management system (43.5%). After adjustment for confounding using multivariable analysis, the odds of C. fetus infection were highest in Adamawa state (P < 0.01), in the pastoral management system (P < 0.01), and in bulls >7 years old (P = 0.01), and tended to be higher in Bos taurus breeds (P = 0.06). There was a strong positive association between the presence of campylobacteriosis and brucellosis (P < 0.01), both within bulls (OR = 8.3) and within herds (OR = 16.0). Trichomonosis was not detected in any herds.

Conclusion

Bovine genital campylobacteriosis is prevalent particularly in the pastoral management system in northern Nigeria, with C. f. venerealis biovar intermedius as the major aetiology. There was a strong positive correlation between the occurrence of campylobacteriosis and brucellosis. No evidence of trichomonosis was found in herds in this study.     

小麦苗期根系性状的全基因组关联分析与优异位点挖掘

【目的】植物根系对水分及营养的获取、作物的生长发育和产量的形成至关重要。挖掘小麦苗期根系性状显著关联的SNP位点,预测相关候选基因,为解析小麦根系建成遗传机制及选育具有优良根系构型的小麦品种奠定基础。【方法】以189份小麦品种组成的自然群体为供试材料,调查2种培养条件（霍格兰营养液和去离子水）下培育21 d的苗期根系总长度（TRL）、根系总表面积（TRA）、根系总体积（TRV）、根系平均直径（ARD）及根系干重（RDW）等5个根系性状,试验进行2次重复,同时结合小麦660K SNP芯片的分型结果进行全基因组关联分析（genome-wide association study,GWAS）。此外,通过序列比对、结构域分析和注释信息预测候选基因,并采用竞争性等位基因特异性PCR(kompetitive allele specific PCR,KASP)技术开发根系性状的分子标记。【结果】霍格兰营养液培养条件下的根系性状变异范围较大,根系整体粗短;而去离子水条件下的根系细长、侧根较多。选用贝叶斯信息与连锁不平衡迭代嵌套式模型（BLINK）、压缩式混合线性模型（CMLM）、固定随机循环概率模型（...