Growth of ADP point seed crystal (100) surface

growth experiments of ammonium dihydrogen phosphate (ADP) point seed crystal were employed. And it is shown that the growth rate of (100) surface increases linearly with the increase of super saturation under the conditions of 0.005 kT/ωs~ 0.03 kT/ωs for phase transition drive force and 20~40 ℃ for the growth temperature. The growth rate of (100) surface increases exponentially with the rise of temperature when drive force is constant. The kinetics mechanism of crystal surface growth is in agreement with the screw dislocation growth under the condition of bulk diffusion transfer mechanism. There is death zone resulting from thermodynamic factors in crystal growth when the drive force is less than the critical value. The growth rate of (100) surface increases nonlinearly with increasing super saturation when drive force is within 0.05 kT/ωs~0.11 kT/ωs. The crystal growth is dominated by the 2D nucleation mechanism with the existence of other growth mechanisms.     

高效液相色谱法测定大鼠比目鱼肌和内侧腓肠肌内ATP·ADP及AMP含量的研究

[目的]比较成年大鼠比目鱼肌和内侧腓肠肌内ATP、ADP及AMP的含量。[方法]采用大体解剖法取出大鼠的比目鱼肌和内侧腓肠肌,置于液氮内研磨成粉末,再分别加入EDTA和HClO4、NaHCO3,经高速冷冻离心取出上清液,用高效液相色谱仪测定。[结果]慢肌(比目鱼肌)ADP的含量多于快肌(内侧腓肠肌),慢肌(比目鱼肌)ATP、AMP的含量少于快肌(内侧腓肠肌)。[结论]使用高效液相色谱仪可以检测出快慢肌的差异。     

Combined effect of bioaugmentation and bioturbation on atrazine degradation in soil

Earthworms, because they change soil physical and chemical properties, are efficient engineers that act on soil microbial community and activity. Thus they may drive pollutant biodegradation in soil such as atrazine mineralization. We hypothesized that earthworms modify the abundance of indigenous soil bacteria and the fate and activity of atrazine-degraders in the soil they engineer by bioturbation. Two bacterial strains were used as bioaugmentation agents: Pseudomonas sp. ADP and Chelatobacter heintzii, which have acquired the capacity to metabolize atrazine by carrying plasmidic atz A, B, C, D, E, F and atzA, B, C, trzD genes, respectively. We analyzed the interactions between earthworms (Lumbricus terrestris) and the indigenous and atrazine-degrading (indigenous and inoculated) bacterial communities by quantifying the 16S rRNA and the atzA gene sequence copies numbers, respectively, in different earthworm microsites. The kinetics of atrazine mineralization were measured to link the bacterial community changes with the degradation function. Digestion by earthworms significantly impacted the number of indigenous bacteria and atrazine mineralization in bioaugmented soils. Regarding the fate of the two atrazine-degraders tested, Pseudomonas sp. strain ADP survived better within the 10 days of experiment than C. heintzii in the bulk soil but the surviving fraction of C. heintzii was still metabolically active and able to mineralize atrazine. A positive “burrow-lining” effect on the atzA sequence copies number was observed in soil whether bioaugmented with C. heintzii or not (i.e. native indigenous atzA) thereby indicating that burrow-linings form a specific ‘hot spot’ for atrazine-degraders. The present study is the first to report the role of earthworms in selecting native catabolic key-genes in soil (indigenous atzA). This catabolic gene selection through earthworm soil bioturbation could be important in sustaining the degradation (detoxification) function of soil.     

甘蔗ADP/ATP转运蛋白酶基因克隆及其序列的生物信息学分析

摘要：【研究目的】甘蔗(Saccharum officinarum Linn) 是C4光合途径作物,有着特殊的能量代谢系统,研究其能量代谢过程的ADP/ATP转运蛋白酶基因具有重要的意义。【方法】本研究采用同源克隆原理和PCR技术克隆甘蔗AAC转运蛋白酶基因,并应用生物信息学方法,对其进行多序列比对分析、物理性质分析、三级结构预测、亚细胞定位、跨膜区域预测和疏水性分析。【结果】克隆获得甘蔗AAC cDNA序列全长为1170bp,包括一个可编码387氨基酸的完整ORF。生物信息学分析显示,AAC家族基因的N端序列相对不保守,C端序列高度保守;其的分子量是42.265 kD,理论等电点是9.79,预测其为稳定的蛋白;GRAVY值为-0.099;含有6个跨膜区域;其6个跨膜螺旋(TM1-TM6)跨越磷脂双分子层结构,盐桥可能是通过中间的3个连接螺旋α1-α3共同构成的;定位在细胞质的概率为60.9%。【结论】本研究获得甘蔗AAC 完整ORF序列,并通过生物信息学预测该基因所编码的蛋白为一个稳定跨膜蛋白,其可能定位在细胞质。这些研究为甘蔗AAC基因的深入研究和应用奠定初步基础。     

Serum bile acids as an indicator of liver disease in dogs

Total serum bile acids were determined in 62 dogs with different primary or secondary liver diseases, using 3α-hydroxysteroid dehydrogenase coupled to nitrobluetetrazolium in a centrifugal analyzer. A reaction time of 4 min was sufficient, yielding a within run coefficient of variation of 7% at 6 µmol/1 and 3% at 27 µmol/1. A reference range of 0–4.4 µmol/1 2 h post prandially was observed. The sensitivity of bile acids as a liver function test was superior to that of alanine and aspartate aminotransferase, alkaline phosphatase, γ-glutamyltransferase and combinations of two of these. The bile acids test detected 36 of 39 patients with a morphological or clinical liver diagnosis. For dogs with heart failure the bile acids test was a markedly more sensitive indicator of secondary liver involvement than alanine aminotransferase or alkaline phosphatase. For secondary liver affections associated with pyometra or epilepsy medication the opposite was the case. Bile acid values in the pooled patient material was not correlated to any of the 4 enzymes measured. For cirrhosis there was positive correlation, however, with the amino transferase values.