嵴病毒（Kobuvirus, KoV）是微RNA病毒科的一个新的属，包括A型爱知病毒-F型爱知病毒（Aichivirus A-F）6个种，目前只在牛和绵羊中检测到Aichivirus D。我们在采用宏基因组技术鉴定某爆发腹泻的山羊场的腹泻病原时，意外的在粪便中发现了Aichivirus D序列，本实验的目的是研究山羊源Aichivirus D的分子特征并调查其与山羊腹泻的联系。根据病毒宏基因组学技术获得的Aichivirus D部分序列设计引物，成功地从腹泻样本获得了一个近乎全长Aichivirus D基因组（8,461 bp），包含7,524 bp 的完整编码框，与绵羊Aichivirus D的遗传关系最近，可能由绵羊Aichivirus D通过重组进化而来，重组区域位于VP1基因。为进一步调查Aichivirus D与山羊腹泻的联系，从3个爆发腹泻的羊场采集了116份2-60日龄的羔羊粪便样本（61份腹泻样本，55份临床健康粪便样本），采用特异性RT-PCR进行了Aichivirus D的检测。结果表明，腹泻样本中Aichivirus D阳性率为55.74% (34/61)，显著高于健康样本(14.55%，P＜0.001)，且其它常见腹泻病原未检出，提示Aichivirus D与山羊腹泻有关。在此基础上，又从9个阳性样本中扩增出完整的VP0、VP3和VP1基因，与绵羊源Aichivirus D相比，山羊源Aichivirus D的VP0、VP3和VP1基因有独特的氨基酸突变和遗传进化特征。总之，本实验首次证明Aichivirus D感染山羊，且该病毒可能与山羊腹泻有关。该病毒与绵羊Aichivirus D的亲缘关系最为密切，可能是由绵羊AichiVirus D 重组进化而来的。这些结果有助于深入了解Aichivirus D的宿主范围和遗传进化。

One concern about the use of transgenic plants is their potential risk to natural enemies. In this study, using the eggs of the rice brown planthopper, Nilaparvata lugens, as a food source, we investigated the effects of Cry1Ab rice on the biological characteristics and functional response of an important predator Cyrtorhinus lividipennis. The results showed that the survival ability (adult emergence rate and egg hatching rate), development (egg duration, nymphal developmental duration), adult fresh weight, adult longevity and fecundity of C. lividipennis on Bt rice plants were not significantly different compared to those on non-Bt rice plants. Furthermore, two important parameters of functional response (instantaneous search rate and handling time) were not significantly affected by Bt rice. In conclusion, the tested Cry1Ab rice does not adversely impact the biological character and functional response of C. lividipennis.

The hand-held soil plant analysis development (SPAD) chlorophyll meter has proved to be a promising tool in evaluating the nitrogen status of the potato and guiding fertilization recommendations. In the process of N evaluation of potato plants and N recommendation, it is critical to establish the threshold SPAD value (SPAD reading), below which nitrogen supplement is required. And taking convenient using into account, the threshold needs to be dynamic throughout the potato growing season so that the users can test their potato plants and make fertilization decision at any growing time of potato. To complete this goal, field experiments with different nitrogen supply levels were conducted in different sites in northern China from 2009 to 2011. The results showed that threshold SPAD values decrease as the growing season progresses for all cultivars and planting sites. By statistical analysis, the threshold regression models were established respectively as: y=−0.003x2−0.0507x+58.213 (y, threshold SPAD value; x, days after emergence) for the potato cultivar Kexin 1, and y=−0.003x2+0.017x+52.489 (y, threshold SPAD value; x, days after emergence) for the cultivar Shepody, from which, the threshold SPAD value at any day after emergence can be calculated.

Twelve fluorescence-labeled microsatellite markers were used to analyze the genetic diversity of 12 domestic duck breeds and 2 wild duck breeds to determine the relationship and origin of Chinese domestic duck breeds. Gene frequency, effective number of alleles (Ne), expected heterozygosity (He), polymorphism information contents (PIC), inbreeding coefficient in population (Fis), standard genetic distance (DS), and genetic distance (DA) were calculated by FSTAT and distance and phylogenetic analysis after the dates which were output from the Microsatellite-Toolkit software. Genetic distances between 12 domestic duck breeds and 2 wild duck breeds were analyzed by variance analysis. Unweighted pair group method with arithmetic mean (UPGMA) and phylogenetic trees used for cluster analysis were structured. The results indicated that 11 loci had medium- or high-level genetic diversity among the 12 loci, which could be efficiently used in the detection of the genetic parameters of each population. The values of He were 0.5414 to 0.7343, those of PIC proved similar, and those of Fis were 0.1101 to 0.3381 among all populations. All breeds were clustered into three groups by UPGMA phylogenetic trees. Banzui duck was clustered into a separate group. Differences of the DA were analysed by t-test. The results showed that difference in DA between the 12 domestic duck breeds and Lvtou duck and the Banzui duck were very significant (P<0.01), indicating that these 12 domestic duck breeds originated from Lvtou wild duck, but not Banzui duck.