史氏鲟♀×达氏鳇♂卵裂间隔τ0与温度的关系

卵裂间隔(τ0)是与温度相关的参数,为早期胚胎发育时期第一次卵裂持续的时间,或连续两次细胞分裂的时间间隔,被广泛用于鱼卵染色体操作中最佳诱导时间的确定上。本文研究了史氏鲟♀×达氏鳇♂受精卵在14～22℃下卵裂间隔τ0与温度的关系,τ0为第一次卵裂(τⅠ)与第二次卵裂(τⅡ)间的时间间隔(τⅡ-τⅠ)。结果表明:在实验温度范围内,史氏鲟♀×达氏鳇♂受精卵τ0随着温度(T)的上升而减小,在14℃下τ0为85.0±1.3 min,22℃下τ0为45.8±2.2 min,两者之间符合线性回归关系:τ0=154.54-4.95T(R2=0.999 0)。22℃为史氏鲟♀×达氏鳇♂胚胎发育的温度上限,超过此温度,正常卵裂的胚胎比例将显著下降(<60%)。     

An international multi-centre prospective study on the efficacy of an intraarticular polyacrylamide hydrogel in horses with osteoarthritis: a 24?months follow-up

Background

Polyacrylamide hydrogel (PAAG) was evaluated recently to treat osteoarthritis (OA) in horses with highly encouraging results; however no long term field-study was done to explore its clinical efficacy and lasting effect. The objective of this study was to evaluate the efficacy of PAAG in improving clinical signs of OA in horses. We hypothesized that lameness grade would significantly improve and the effect would last at least 2&#x000a0;years in osteoarthritic joints treated with PAAG. Forty three horses older than 2&#x000a0;years with OA in only one joint based on clinical evaluation, intra-articular anaesthesia and imaging (radiography) were included in this study. Horses were injected with 2&#x000a0;ml of PAAG into the affected joint and were followed up at 1, 3, 6, 12 and 24&#x000a0;months. Efficacy of PAAG was evaluated by blinded clinical assessment of lameness. Adverse reactions to joint injection were assessed. Data relating to case details, type of activity, joint and limb involved, lameness duration, lameness grading, previous joint treatment, joint effusion grading, radiographic grading, and owner assessment were recorded. Factors associated with the outcome measure &#x0201c;lameness grading&#x0201d; were analyzed using generalized linear mixed model for logistic regression.

Results

At 1, 3, 6, 12 and 24&#x000a0;months follow-up, 59%, 69%, 79%, 81/% and 82.5% of horses were non-lame respectively. Reduction of joint effusion was observed over time. No side effect was observed in the treated joints. There was a significant decrease in lameness grade from baseline to 1, 3, 6, 12 and 24&#x000a0;months (P&#x02009;&#x0003c;&#x02009;0.0001) and a significant positive association with joint effusion (P&#x02009;&#x0003c;&#x02009;0.0001). Estimates for odds ratio (OR) showed that the effect of treatment increased over time (OR for lower lameness from month 1 to month 24 relative to baseline increased from 20 to 58).

Conclusions

PAAG significantly alleviated lameness and joint effusion in osteoarthritic joints. PAAG is a safe and lasting (at least 24&#x000a0;months) OA treatment in horses. PAAG is a promising new treatment for OA in horses.     

零价铁降解水中的阿特拉津

本文应用零价铁(Fe0)技术,以阿特拉津为目标污染物,考察了零价铁的效应,研究了不同零价铁投加量、不同溶液初始pH值等因素对阿特拉津降解效果的影响。结果表明,零价金属铁脱氯降解阿特拉津,随着金属铁质量的增加,阿特拉津的降解率也会增加;溶液初始pH值2～11时,阿特拉津降解率随其低pH值的增加而减小,可以促进零价金属铁的腐蚀,有利于阿特拉津降解。     

饲粮粗蛋白和蛋氨酸水平对育雏期笼养金定鸭性能的影响

采用饲养试验、代谢试验和屠宰试验研究在等能条件下 (ME :1 1 .9MJ kg) ,不同蛋白质水平 (CP :1 7% ,1 9% ,2 1 % )和蛋氨酸水平 (Met CP :0 .0 2 0、0 .0 2 5、0 .0 30 )完全交叉组成的 9种饲粮对笼养金定鸭育雏期 (0～ 4周龄 )生长性能、养分利用、体成分沉积方面的影响。结果表明 :不同蛋白质水平饲粮对试鸭 0～ 4周龄的体增重、采食量、蛋白、能量、钙、磷的利用率以及蛋白、钙、磷沉积量影响显著 (P <0 .0 5或P <0 .0 1 ) ;不同蛋氨酸水平饲粮对试鸭的上述指标 ,除钙利用率、磷沉积量外 ,影响均不显著 (P >0 .0 5)。氮存留率与能量、钙、磷的利用率随饲粮CP(% )的升高而是降低 ,且各水平间差异显著 (P <0 .0 5) ,却随蛋氨酸水平的升高而升高。蛋白水平与蛋氨酸水平的互作结果为 :对氮存留率、能量和磷的利用率影响差异不显著 (P >0 .0 5) ,且以第 3组 (CP =1 7% ,Met CP =0 .0 30 )效果最好 ,而钙的利用率第 3组效果也较好。因此 ,在本试验条件下 ,饲粮适宜粗蛋白和蛋氨酸水平分别为 :CP(% ) =1 7,Met CP =0 .0 30。     

Studies on the magnesium metabolism of crops (Part 1) the balance among magnesium,calcium and pot assLum in free and bound forms at the flowering stage of soy-bean plants

In the later nineteenth century, it was established that magnesium is one of the essential elements to plant life. In 1902 Loew¹⁾ and his pupils suggested the necessity of calcium-magnesium- balance in culture solution for the proper growth of the plant. Then, in 1906, it was established that, as first shown by Willstatter, magnesium is one of the constituents of chlorophyll and when this element is lacking, a chlorosis occurs. Dickson²⁾, in 1918, described about the feature of oat plant grown in a magnesium deficient nutrient solution. At that time, it was thought that magnesium was generally contained in the soil more abundantly than the plant required. So this element scarcely received attention. Garner et al.³⁾, in 1923, observed that chlorosis of tobacco plant, so-called sand drown was cured by applying magnesium to the soil. Similar observation was made in 1929 by Jones⁴⁾ on the chlorosis of corn plant. Since that time the magnesium deficiency in all crops was observed everywhere by a great many investigators. In Japan magnesium deficiency in the field has attracted attention from 1951.     

Acute and Subacute Metabolic and Endocrine Effects of Clenbuterol in Female Pigs

The aim of the study was to assess the relationship between acute and subacute metabolic and endocrine effects after intravenous administration of the 0mvk28608pk/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">₂-adrenergic agonist clenbuterol in a growth-promoting dose to female pigs. Acute metabolic and endocrine effects were assessed by measuring the blood glucose, serum insulin and nonesterified fatty acid (NEFA) concentrations during 300 min after a single administration of clenbuterol. Significantly higher serum insulin and NEFA concentrations (19.90±2.50 0mvk28608pk/xxlarge956.gif" alt="mgr" align="MIDDLE" BORDER="0">U/ml, p<0.01, and 0.69±0.04 mmol/L, p<0.001, respectively) were measured 30 min after the preprandial administration of clenbuterol in female pigs. Over the same period, the levels of blood glucose (4.42±0.30 mmol/L) showed no difference from those of control pigs. The postprandial serum NEFA concentration decreased moderately during 210 min after feeding. Postprandial blood glucose and insulin concentrations increased and reached maximal levels 120 min after clenbuterol administration (10.91±0.60 mmol/L and 85.22±7.24 0mvk28608pk/xxlarge956.gif" alt="mgr" align="MIDDLE" BORDER="0">U/ml, respectively), and returned to basal levels at 300 min (4.20±0.21 mmol/L and 7.75±1.60 0mvk28608pk/xxlarge956.gif" alt="mgr" align="MIDDLE" BORDER="0">U/ml, respectively) after the administration of clenbuterol. Subacute metabolic and endocrine effects were assessed by measuring the blood glucose, serum insulin and NEFA concentrations for 21 days after the repeated doses of clenbuterol. In addition, the influence of clenbuterol administration on the endocrine regulation of the onset of the next expected oestrus in female pigs was assessed by measuring their serum 170mvk28608pk/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-oestradiol and progesterone concentrations. Blood glucose, serum insulin and NEFA concentrations after the last administration of clenbuterol did not differ significantly from those in control animals. The onset of the next expected oestrus occurred regularly without any significant difference in serum 170mvk28608pk/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-oestradiol or progesterone concentrations between the treated (9.83±2.60 pg/ml and 0.15±0.03 ng/ml) and control pigs (8.52±2.70 pg/ml and 0.25±0.06 ng/ml). The study results suggest the duration of intravenous administration of clenbuterol in a growth-promoting dose necessary to influence the metabolic and endocrine activities in female pigs.     

The relative contributions of soil hydrophilicity and raindrop impact to soil aggregate breakdown for a series of textured soils

Soil aggregate breakdown is the first key factor that causes soil erosion. At present, research on the mechanisms of soil aggregate breakdown during rainfall is common. However, the research to on quantifying the relative contributions of internal and external forces to aggregate breakdown remains limited. This paper was conducted to analyse the relative contribution of internal and external forces to aggregate disintegration and the factors affecting aggregate stability during rainfall. Soil aggregates with a series of textures were selected as test soil samples; deionized water was employed as the soaking solution and rainfall material in static disintegration experiments and rainfall simulation tests. The effect of internal force (soil hydrophilicity) on aggregate disintegration was analysed by the static disintegration method, and the combined effects of internal force (soil hydrophilicity) and external force (raindrop impact) on soil aggregate breakdown were analysed by rainfall simulation experiments. The results indicated that external force caused more severe soil aggregate breakdown than internal force, and the crushed aggregate was mainly distributed in the range of 2–0.25 mm. With increasing rainfall kinetic energy, the degree of aggregate breakdown increased gradually, and the degree of aggregation of the soil particles decreased gradually. Furthermore, soil aggregates with a high clay content (> 30%) were more stable than medium-clay (20–30%) and low-clay (< 20%) soil aggregates, and the correlation coefficient provided a good representation of the relationship between the clay content and soil aggregate stability index (ASI). Therefore, external force contributed more to soil aggregate breakdown than internal force during rainfall, and clay plays an important role in aggregate stability. The results of this study are of great significance for elaborating the mechanism and factors affecting aggregate breakdown.     

棉铃虫小分子热激蛋白sHSP22.0基因的克隆及表达谱分析

棉铃虫Helicoverpa armigera是一种重要的农业害虫,本文旨在研究小分子热激蛋白在其生长发育过程、抵御高温及Cry1Ac杀虫蛋白中的功能.利用PCR结合RACE技术克隆了棉铃虫sHSP22.0(small heat shock pro-tein 22.0)基因,通过生物信息学软件分析了棉铃虫sHSP22....     

玉米当代杂种优势研究回顾

回顾了20世纪70年代以来,国内外玉米当代杂种优势研究的历程,总结和归纳了该研究领域的一些主要成果,并对尚需进一步研究的问题做了探讨。