水体阿特拉津残留对水葱生物量及生理特性的影响

利用营养液水培法, 研究了5个阿特拉津(atrazine)浓度(1、2、4、8和16 mg·L^-1)下水葱(Scirpus tabernaemontani)鲜重、叶片相对含水量(RWC)、丙二醛(MDA)含量、过氧化物酶(POD)活性、根系活力和叶绿素含量等的变化。结果表明, 水葱在阿特拉津胁迫下, 鲜重、RWC、叶绿素含量均有不同程度的下降, 根系活力和POD活性降低, 同时MDA含量上升, 膜脂过氧化程度加剧。由于阿特拉津的降解, 这种不良影响随处理时间的延长而减弱。但其对叶绿素含量的影响具持久性; 培养60天内, 叶绿素含量仍显著低于正常水平。阿特拉津浓度越高, 对水葱的植物毒性越高, 当浓度高于8 mg·L^-1时, 水葱的生长和生理活动受到显著影响(p < 0.05); 低于1 mg·L^-1时, 与对照无显著差异。     

氮素对不同品种烤烟叶片衰老、光合特性及产量和品质的影响

以豫烟5号、豫烟7号和NC89为材料,研究氮素对不同品种烤烟叶片衰老、光合特性及产量和品质的影响.结果表明：增施氮素可显著增强烤烟叶片超氧化物歧化酶(SOD)活性,降低丙二醛(MDA)含量,提高叶绿素含量,增强光合性能,从而延缓烤烟叶片衰老.与豫烟5号和NC89相比,豫烟7号叶片叶绿素含量较低,光合性能较弱,SOD活性低,MDA含量高,叶片衰老较快.与60和75 kg·hm^-2施N处理相比,45 kg·hm^-2 施N处理的烟叶均价、产值、上等烟比例均最高,且化学品质指标较好,符合优质烟叶要求.表明不同品种烤烟衰老生理特性有明显差异;氮素营养对烤烟叶片衰老、产量和品质有明显的调节作用;适量施氮可提高烟叶品质,获得较高的经济效益.     

厦门常见观赏竹在园林造景中的应用

在对厦门岛内外公园、绿地竹类植物调查的基础上,选择常见观赏竹31种,分析其观赏特性,并阐述其在现代园林绿化中的应用。     

Development and characterization of a continuous cell line PSCF from Puntius sophore

A continuous Puntius sophore caudal-fin (PSCF) cell line of the pool barb Puntius sophore, an important freshwater food and ornamental fish of Asia and South East Asia, was developed from the caudal fin for the first time. The cell line was optimally maintained at 28° C in Leibovitz-15 (L-15) medium supplemented with 10% foetal bovine serum (FBS). The cytogenetic analysis revealed a diploid count of 50 chromosomes at 25th and 50th passage and 52 chromosomes at passage 70, 85 and 100. The viability of the PSCF cell lines was 75% after 6 months of storage in liquid nitrogen (-196° C). The most striking feature of the PSCF cells was its high increased growth ratio as evident from the population doubling time of 25 h at passage 100. The origin of the cell lines was confirmed by the amplification of 581 and 655 bp fragments of 16 S rRNA and cytochrome oxidase subunit I (COI) of mitochondrial DNA (mtDNA) genes, respectively. The PSCF cells were successfully transfected with green fluorescent protein (GFP) reporter plasmids and the expression of GFP gene in the cells indicated the potential utility of the cells in gene expression studies.     

Community-wide assessment of protein-interface modeling suggests improvements to design methodology

The CAPRI (Critical Assessment of Predicted Interactions) and CASP (Critical Assessment of protein Structure Prediction) experiments have demonstrated the power of community-wide tests of methodology in assessing the current state of the art and spurring progress in the very challenging areas of protein docking and structure prediction. We sought to bring the power of community-wide experiments to bear on a very challenging protein design problem that provides a complementary but equally fundamental test of current understanding of protein-binding thermodynamics. We have generated a number of designed protein-protein interfaces with very favorable computed binding energies but which do not appear to be formed in experiments, suggesting that there may be important physical chemistry missing in the energy calculations. A total of 28 research groups took up the challenge of determining what is missing: we provided structures of 87 designed complexes and 120 naturally occurring complexes and asked participants to identify energetic contributions and/or structural features that distinguish between the two sets. The community found that electrostatics and solvation terms partially distinguish the designs from the natural complexes, largely due to the nonpolar character of the designed interactions. Beyond this polarity difference, the community found that the designed binding surfaces were, on average, structurally less embedded in the designed monomers, suggesting that backbone conformational rigidity at the designed surface is important for realization of the designed function. These results can be used to improve computational design strategies, but there is still much to be learned; for example, one designed complex, which does form in experiments, was classified by all metrics as a nonbinder.     

二甲基亚砜毒性研究

二甲基亚砜（Dimethyl sulfoxide DMSO）是一种含硫有机化合物,被誉为＂万能溶剂＂,广泛用作溶剂和反应试剂。在医药工业中,DMSO可直接用作某些药物的原料及载体。DMSO本身有消炎止痛,利尿,镇静等作用,亦誉为＂万灵药＂,常作为止痛药物的活性组分添加于药物之中。DMSO也是一种渗透性保护剂,能够降低细胞冰点,减少冰晶的形成,减轻自由基对细胞损害,改变生物膜对电解质、药物、毒物和代谢产物的通透性。DMSO作为组蛋白去乙酰化酶抑制剂（Histone Deacetylases-inhibitor HDACi）的一种,同样具有恢复组蛋白的乙酰化与去乙酰化平衡,抑制细胞程序性死亡,修复DNA双螺旋结构,抗放射性损伤,抗炎症反应及抗癌作用。鉴于其应用广泛,本文就其物理特性及毒性研究做一综述。