实验感染肝片吸虫山羊和大鼠血清花生四烯酸代谢物的变化研究

实验一选择9只健康、6-10月龄雄性白山羊，经粪便学检查和Dot-ELISA检测，确认无肝片吸虫感染，随机分成感染组（n=5)和对照组（n=4)，试验组每只一次口服接种150个肝片吸虫囊蚴，每周定时从颈静脉采集感染前（0周）和感染后23周山羊血液一次，分离血浆，实验二将60只大鼠随机分成感染组（n=30)和对照组（n=30)，感染组大鼠一次口服25个囊蚴，对照组不感染，于感染前（0周）和感染后（1，3，5，7，9周）采集血样，分别测定试验组和对照组羊和鼠花生四烯酸代谢物6-酮-前列腺素F1α（6-keto-PGF1α）和血栓素B2（TXB2）的变化。结果表明肝片吸虫感染后，山羊血浆中TXB2水平变化，在1-3周与对照组相比无显著差异，从第5周开始到实验结束，试验组血浆中TXB2水平均显著或极显著地高于对照组，大鼠血栓素水平在感染后前5周逐步下降，以后急剧上升，至实验结束时显著高于对照组；而整个实验期间，两种动物血浆中6-keto-PGF1α水平变化不显著，提示肝片吸虫感染后，机体发生多种功能的改变，花生四烯酸代谢物参与了肝片吸虫病的发展过程。     

Effects of donor cells’ sex on nuclear transfer efficiency and telomere lengths of cloned goats

The aim of this study was to investigate the effects of donor cells’ sex on nuclear transfer efficiency and telomere length of cloned goats from adult skin fibroblast cells. The telomere length of somatic cell cloned goats and their offspring was determined by measuring their mean terminal restriction fragment (TRF) length. The result showed that (i) reconstructed embryos with fibroblast cells from males Boer goats obtained significantly higher kids rate and rate of live kids than those of female embryos and (ii) the telomere lengths of four female cloned goats were shorter compared to their donor cells, but five male cloned goats had the same telomere length with their donor cells, mainly due to great variation existed among them. The offspring from female cloned goats had the same telomere length with their age‐matched counterparts. In conclusion, the donor cells’ sex had significant effects on nuclear transfer efficiency and telomere lengths of cloned goats.     

Resistance to an herbivore through engineered cyanogenic glucoside synthesis

The entire pathway for synthesis of the tyrosine-derived cyanogenic glucoside dhurrin has been transferred from Sorghum bicolor to Arabidopsis thaliana. Here, we document that genetically engineered plants are able to synthesize and store large amounts of new natural products. The presence of dhurrin in the transgenic A. thaliana plants confers resistance to the flea beetle Phyllotreta nemorum, which is a natural pest of other members of the crucifer group, demonstrating the potential utility of cyanogenic glucosides in plant defense.     

Predicting silage maize yield and quality in Sweden as influenced by climate change and variability

Abstract

In recent decades European silage maize production has extended northwards, into Scandinavia, and the importance of maize in fodder production has increased substantially. For the northward expansion of maize production it is of interest to evaluate both the role of climate change that has occurred already, and scenarios for possible future climate change. The aim of this study was to assess for Swedish climatic conditions, the annual variation in silage maize yield and quality (dry weight and starch contents) of cultivars currently grown in Germany.

The MAISPROQ simulation model currently used in German maize production was applied to evaluate the effects of (i) cultivar differences (four cultivars; four sites; 2003–2009), (ii) intra-regional variation among ten sites representing three regions (two cultivars; 2003–2009), and (iii) climatic variability among two historical periods during 1961–2009 and three future periods during 2011–2100 using A2-emission climate scenarios and the Delta-method (two cultivars; four sites).

Forage quality assessments strongly influenced the assessments of harvest time and thereby the yield. Changes in simulated yield of the tested cultivars were high for the past climate, but relatively small under future climatic conditions due to earlier harvest caused by improved forage quality. By the end of the 21st century an appropriate fodder quality would be achieved every year in the south of Sweden, whereas in the middle of Sweden (60°N) about 30% of the years would not be successful, even for the earliest cultivar. In the east, increased water stress counteracted the positive effect of a prolonged growing season. It was concluded that adaptation of field experiments to model calibration requirements remains to be done, in order to enable extrapolation of observations from Swedish field trials to a changing future climate.     

Root biomass dynamics in a semi-natural grassland exposed to elevated atmospheric CO2 for five years

The effects of elevated atmospheric CO₂ on root dynamics were studied in a semi-natural grassland in central Sweden during five consecutive summer seasons. Open-top chambers were used for ambient and elevated (+350 μmol mol^?1) concentrations of CO₂, and chamberless rings were used for control. Root dynamics were observed in situ with minirhizotrons during the five summers and root biomass production was measured with root in growth cores during the last two years, from which total root biomass was estimated for each of the five years. The elevated CO₂ treatment showed both a greater increase in root numbers during the early summer and a greater decline in root numbers during autumn and winter than the ambient CO₂ treatment. Mean root production under elevated CO₂ was 50% greater than ambient CO₂ during the five years, and the difference increased from +25% in the first year to +80% in the last two years. Conversely, during the same period, the elevated to ambient CO₂ difference in shoot biomass decreased from +50% to +5%. This resulted in a dramatic change in root to shoot ratios in elevated CO₂ compared with the ambient treatment, which increased from ?15% in 1996 to +70% in 2000. Similar differences were seen between elevated CO₂ and the chamberless grown control plants, where root to shoot ratios increased steadily from ?47% in 1996 to +27% in 2000. Less dynamically, the root to shoot ratios of ambient CO₂ grown plants compared with the chamberless control plants were consistently ?29%±6% during the experimental period. In conclusion, during the 5 years this grassland was studied, there was a clear shift in plant biomass partitioning from above to below ground for plants exposed to elevated CO₂.     

Biochemical response and induced resistance against anthracnose (Colletotrichum camelliae) of camellia (Camellia pitardii) by chitosan oligosaccharide application

This study demonstrated that disease resistance against anthracnose (caused by Colletotrichum camelliae) in camellia (Camellia pitardii) could be induced by chitosan oligosaccharide (COS) applied to leaves at 50 µg/ml. The induced resistance lasted for 10–15 days, with the optimum induced effect against anthracnose occurring by the third day. Following treatment with C. camelliae alone, COS alone and C. camelliae and COS combined, camellia plants showed different responses, which included the activity of H₂O₂, the defence‐related enzymes, such as polyphenol oxidase, peroxidase, catalase, phenylalanine ammonialyase, and concentration of soluble proteins. Plants that received COS treatments consistently had higher levels of biochemical activity than plants not treated with COS. Assessment of anthracnose severity on infected plants, as evidenced by reduced lesions on leaves, indicated that COS‐induced camellia plants had significantly lower disease ratings. To our knowledge, we are first to report the inducement by COS on camellia against anthracnose.     

实验感染肝片吸虫山羊血液T、B淋巴细胞比例及激素水平变化

为了深入了解动物感染肝片吸虫后免疫细胞和内分泌活动的变化，将6只健康山羊均分为感染Ⅰ、Ⅱ组及对照组。Ⅰ、Ⅱ组分别一次性口服感染肝片吸虫囊蚴200、500个／只，试验期17周，每周定时采血，测定血浆T、B淋巴细胞比例、皮质醇、胰岛素、甲状腺激素（T3、T4）等。结果表明，Ⅰ、Ⅱ组山羊T淋巴细胞（％）分别从感染后4、6周开始低于或显著低于对照组，直至17周；而淋巴细胞（％）变化与之相反。Ⅰ、Ⅱ组山羊血浆皮质醇变化较大，总体水平高于对照组；T3、T4水平从第4周开始逐渐低于对照组，且在极低的水平上变动；Ⅰ、Ⅱ组胰岛素水平与对照组相近。揭示山羊急性感染肝片吸虫后，内分泌活动紊乱，体内细胞免疫反应抑制，而体液免疫反应增加，表现出山羊对肝片吸虫感染的耐受力和抵抗力较弱的特点。     

苏皖水牛肝片吸虫和前后盘吸虫感染情况的调查

苏皖两省１０县（市）共调查３０２农户的３０７头水牛,粪便学检查肝片吸虫阳性４３头,阳性率１４．０％,其中安徽的阳性率为１１．６１％（１８／１５５）,江苏阳性率为１６．４８％（２５／１５２）;母牛阳性率为１１．８％,公牛为１１．４％;前后盘吸虫阳性１７０头,阳性率为５５．４％（１７０／３０７）,其中安徽的阳性率为５８．１％（９０／１５５）;江苏的阳性为５２．６％（８０／１５２）,母牛的阳性率为６０．１％（１３７／２２８）,公牛的阳必国４１．８％（３３／７９）,两种吸虫的阳性率均呈现随年龄增加而提高的趋势,经统计学分析,两种吸虫的感染与地形无显著差异（Ｐ〉０．０５）,肝片吸虫的感染与性别、年龄亦无显著差异（Ｐ〉０．０５）,但对前后盘吸虫来说,感染与性别、年龄的差异显著（Ｐ〈０．０５）。而各县间两种吸虫感染则有显著关