地下水埋深对春玉米田土壤水分及产量的影响

通过6种地下水位控制处理和对照春玉米试验,探讨了地下水埋深对春玉米农田土壤水分、产量以及水分利用效率的影响。结果表明,地下水埋深对春玉米0～100cm层次土壤水分的影响较大。地下水位越浅这种影响显得越明显;无论地下水埋深深浅,田间累计地下水补给量变化规律可分为4个阶段,即稳定增长期、缓慢增长期、快速增长期和趋于稳定期。地下水位越高,累计地下水补给量越大,土壤排水量越大。较大降雨后土壤开始排水日期随着地下水埋深加深而滞后;地下水埋深1.0m时春玉米产量和水分利用率最高。地下水位在1.0m以下时,水分利用效率随地下水位加深而减少。     

The Influence of Oxygen Tension on Cumulus Cell Viability of Canine COCs Matured in High-Glucose Medium

High in vitro oxygen (O₂) tensions are associated with enhanced levels of reactive oxygen species and cumulus oocyte complex (COC) apoptosis. The objective of this study was to determine the influence of O₂ tension on cumulus cell (CC) viability from canine oocytes. Cumulus oocyte complexes were distributed into three groups (CG, T20 and T5) and two O₂ tension levels (20% and 5%). The control group (CG) was matured in vitro in a humidified atmosphere with 5% CO₂ in air in TCM199 with 26.19 m m sodium bicarbonate, 10% (v/v) foetal calf serum (FCS), 0.10 m m gentamicin, 0.20 m m pyruvic acid, 20 μg/ml oestradiol, 0.5 μg/ml follicle-stimulating hormone, 0.03 IU/ml human chorionic gonadotropin, and 1.0 μg/ml human somatotropin. Groups T20 and T5 were matured under 20% or 5% O₂ tensions respectively in a high-glucose medium, without FCS. T20 and T5 were as CG, and supplemented with 0.1% Polyvinyl Alcohol, and 5.5 m m glucose. After 48 h of IVM, CCs from COCs were stained with propidium iodide (1.50 m m ). The results showed that viability of CCs (cytoplasmic features and nuclear morphological integrity) was different for the three groups. Rates of apoptosis were at 57.9% (521/900) for CG, 54.4% (490/900) for T20 and 38.9% (350/900) for T5 (p < 0.001). Predominant features in apoptotic cells (n = 1361) were DNA nuclear fragments (94.0%). It was concluded that CCs of canine COCs cultured in high-glucose medium showed significantly less apoptosis than those cultured in medium with FCS. Low O₂ tension was efficient in reducing apoptosis in canine CCs.     

Feline Ilial Fractures: A Prospective Study of Dorsal Plating and Comparison with Lateral Plating

Objective— To (1) report a technique for repair of feline ilial fractures using a dorsally applied bone plate and (2) compare outcome with cats treated by a lateral plate.
Study Design— Prospective study.
Animals— Cats (n=10) with iliac fractures.
Methods— Cats with ilial fractures (January 2005–December 2006) were treated by application of a dorsally applied bone plate. Immediate postoperative radiographs were compared with those taken 4–6 weeks later to assess screw loosening, screw purchase, and pelvic canal narrowing. Owners were contacted for medium-term (>3 month) follow-up. Data were compared with a report of outcome after lateral plating (LP) in 21 cats.
Results— Mean (± SD) screw purchase (89 ± 11 mm) was significantly greater ( P <.01) with a dorsal plate compared with a lateral plate (33 ± 8 mm). Significantly more screws ( P <.01) were used with a dorsal plate (median, 7) compared with a lateral plate (median, 6). Significantly less postoperative pelvic canal narrowing developed in the dorsal plating group between postoperative and 4–6-week follow-up radiography compared with the LP group (2% versus 15%, P <.01).
Conclusion— Dorsal plating of feline ilial fractures results in significantly less screw loosening and pelvic canal narrowing at 4–6 weeks after surgery compared with LP.
Clinical Relevance— Dorsal plating of feline iliac fractures may reduce complications associated with pelvic canal narrowing such as constipation and megacolon.     

奶牛围产期低血钙发生状况及其调节作用

为了解奶牛围产期低血钙发生状况及其调节作用,本试验选取围产期经产的健康奶牛20头,分别对其产前21d、14d、7d、产后7d、14d、21d及分娩当天血中钙(Ca)、磷(P)、碱性磷酸酶(ALP)、羟脯氨酸(HYP)、甲状旁腺素(PTH)、骨钙素(BGP)、降钙素(CT)浓度进行测定.按血钙水平将试验奶牛按上述时间点均分为对照组(血钙正常)和低血钙组.结果显示:奶牛在产前21d至产后21d低血钙发生率分别为:0%、45%、20%、80%、25%、15%、10%.对照组奶牛血浆Ca、BGP的浓度产前14d到产后21d显著高于低血钙组(P<0.05),ALP、HYP在产前7d到产后21d显著高于低血钙组(P<0.05).两组奶牛血浆P浓度在围产期无显著差异(P>0.05).对照组血浆CT浓度在产前7d和分娩当天显著低于低血钙组(P<0.05),其他时间点差异不显著(P>0.05);对照组血浆PTH浓度在产前7d到产后21d时显著低于低血钙组(P<0.05).结论:奶牛围产期易发生低血钙,以分娩时发生率最高.奶牛围产期易发低血钙与钙代谢调节激素未能发挥其动员骨钙的调节作用有关.     

东北马鹿肌肉生长抑制素基因序列的克隆、编码氨基酸序列及结构特征分析

以与东北马鹿物种最近的牛(Bos taurus cattle,序列号为AB076403)的肌肉生长抑制素(myostatin,MSTN)基因序列为模版,根据该基因保守序列进行引物设计,扩增产物连接入pMD18-T载体,克隆出3个外显子片段.根据5′-GU-AG-3′规则和同源基因比对拼接出带有部分5′、3′末端的cDNA,并采用生物信息学技术对编码氨基酸序列进行蛋白质同源性比较和二级、三级结构等分析.结果表明:所获序列全长为1 128 bp,编码375个氨基酸;具有较明显的螺旋、片层和无规卷曲等二级结构;有1个较明显的跨膜区和1个疏水区,并发现明显的信号肽和糖基化位点.三级结构同源建模预测结果显示与Human Activin A的相似性为42%.结果说明东北马鹿和其他哺乳类生物的肌肉生长抑制素基因之间关系密切,并同属于TGF-β家族.     

The effect of fermented apple diet supplementation on the growth performance and meat quality in finishing pigs

The objective of the present study was to investigate the effect of fermented apple diet (FAD) supplementation on the growth performance and meat quality in finishing Berkshires. The FAD was made from dropped apple mixed with rice bran and barley bran. Until 81 ± 1 kg live weight at 133 ± 1 days, the animals were fed a growing diet, after which experimental samples were fixed at 0, 2, 4 and 6% FAD as C, T1, T2 and T3 in the finishing diets. Growth performance, ADG, ADFI and feed efficiency were improved in T1 than other groups. In carcass parameters, carcass weight was higher ( P  < 0.05) in T1 than in other groups. In meat quality, moisture and crude protein contents decreased ( P  < 0.05) by addition of FAD. pH₂₄ and WHC were higher ( P  < 0.05) in T1 than other groups. In sensory evaluation, marbling of fresh meat and tenderness, juiciness, flavor and overall acceptability of cooked meat were improved by the addition of FAD. According to the results of our experiment, FAD can be used for improvement of meat quality parameters.     

Flavonol glycosides and novel iridoid glycoside from the leaves of Morinda citrifolia

One new iridoid glycoside and five known flavonol glycosides have been isolated from the leaves of Morinda citrifolia. The new iridoid exists as an epimeric mixture in solution. Complete assignments of the proton and carbon chemical shifts for the individual epimers were accomplished on the basis of high-resolution 1D and 2D NMR data. Their antioxidative activities were measured. All of these compounds showed DPPH free radical scavenging activity at the concentration of 30 microM.     

Forest vegetation responses to climate and environmental change: A case study from Changbai Mountain, NE China

The distribution of plant species has always been altered by changing climatic conditions. Nonetheless, the potential for species’ range shift responses has recently become severely limited, as exceptionally fast temperature changes coincide with a high degree of anthropogenic habitat fragmentation. This study provides rare insights into the effects current temperature increases have on pristine temperate forest ecosystems, using the forests of Changbai Mountain, NE China, as a case study. On the northern slopes of the mountain at elevations between 750 and 2100 m, the composition of trees, shrubs and herbaceous species was recorded on 60 plots in 1963 and 2006/07. Multiple linear regression (MLR) and canonical correspondence analysis (CCA) were used to establish the response of plant diversity and plant distribution patterns to environmental conditions. Climatic factors proved important in explaining the spatio-temporal trends within the vegetation. The composition of dominant trees remained mostly unchanged over the last 43 years, reflecting a very slow response of the forest canopy to environmental change. The composition of young trees, shrubs and herb species showed varied changes in the different forest types. A homogeneous species composition in the cohort of regenerating trees indicates an increased future uniformity in the mixed broadleaved and coniferous forest. The understory vegetation of high elevation birch forests was invaded by floristic elements of the lower-elevation coniferous forests. Both these trends pose potential threats to forests plant diversity. Future research investigating climate change responses in forest canopy composition needs to be based on even longer timescales, while investigations in the near future need to pay particular attention to the changes in the distribution of rare and threatened herbaceous species.     

Rapidly quantitative detection of Nosema ceranae in honeybees using ultra-rapid real-time quantitative PCR

BackgroundThe microsporidian parasite Nosema ceranae is a global problem in honeybee populations and is known to cause winter mortality. A sensitive and rapid tool for stable quantitative detection is necessary to establish further research related to the diagnosis, prevention, and treatment of this pathogen.ObjectivesThe present study aimed to develop a quantitative method that incorporates ultra-rapid real-time quantitative polymerase chain reaction (UR-qPCR) for the rapid enumeration of N. ceranae in infected bees.MethodsA procedure for UR-qPCR detection of N. ceranae was developed, and the advantages of molecular detection were evaluated in comparison with microscopic enumeration.ResultsUR-qPCR was more sensitive than microscopic enumeration for detecting two copies of N. ceranae DNA and 24 spores per bee. Meanwhile, the limit of detection by microscopy was 2.40 × 10⁴ spores/bee, and the stable detection level was ≥ 2.40 × 10⁵ spores/bee. The results of N. ceranae calculations from the infected honeybees and purified spores by UR-qPCR showed that the DNA copy number was approximately 8-fold higher than the spore count. Additionally, honeybees infected with N. ceranae with 2.74 × 10⁴ copies of N. ceranae DNA were incapable of detection by microscopy. The results of quantitative analysis using UR-qPCR were accomplished within 20 min.ConclusionsUR-qPCR is expected to be the most rapid molecular method for Nosema detection and has been developed for diagnosing nosemosis at low levels of infection.     

Monitoring distances travelled by horses using GPS tracking collars

Objective The aims of this work were to (1) develop a low-cost equine movement tracking collar based on readily available components, (2) conduct preliminary studies assessing the effects of both paddock size and internal fence design on the movements of domestic horses, with and without foals at foot, and (3) describe distances moved by mares and their foals. Additional monitoring of free-ranging feral horses was conducted to allow preliminary comparisons with the movement of confined domestic horses. Procedures A lightweight global positioning system (GPS) data logger modified from a personal/vehicle tracker and mounted on a collar was used to monitor the movement of domestic horses in a range of paddock sizes and internal fence designs for 6.5-day periods. Results In the paddocks used (0.8–16 ha), groups of domestic horses exhibited a logarithmic response in mean daily distance travelled as a function of increasing paddock size, tending asymptotically towards approximately 7.5 km/day. The distance moved by newborn foals was similar to their dams, with total distance travelled also dependent on paddock size. Without altering available paddock area, paddock design, with the exception of a spiral design, did not significantly affect mean daily distance travelled. Feral horses (17.9 km/day) travelled substantially greater mean daily distances than domestic horses (7.2 km/day in 16-ha paddock), even when allowing for larger paddock size. Conclusions Horses kept in stables or small yards and paddocks are quite sedentary in comparison with their feral relatives. For a given paddock area, most designs did not significantly affect mean daily distance travelled.