An insight into vertebral fractures

European Spine Journal -     

藏波罗花根中两个酚苷的分离纯化、结构鉴定和抗氧化活性研究(英文)

利用生物活性跟踪法,通过硅胶吸附柱色谱、反相C18柱色谱和反相制备型HPLC,从藏波罗花的根中筛选到两个化合物。通过ESI-MS、GC-MS、1D-和2D-NMR进行结构鉴定,确定为acteoside(1)和isoacteoside(2)。1和2的-OH清除活性与苯甲酸接近,1和2的-OH及O-2-清除活性均远远高于维生素C,1和2的肝组织LPO抑制活性也高于BHT或维生素C,1和2在保护红细胞免受氧化损伤的活性也高于维生素C。在0.015 6至0.500 0 mg·mL-1浓度范围,1和2的-OH清除活性与浓度成正相关关系。在0.001 9至0.250 0 mg·mL-1浓度范围,随着浓度的增大,1和2的肝组织LPO抑制活性不断增强;但在0.250 0至1.000 0 mg·mL-1浓度范围,随着浓度的增大,LPO抑制活性反而有轻微的下降。     

Single mutation converts mild pathotype of the Pepino mosaic virus into necrotic one

Pepino mosaic virus (PepMV) is a member of the Flexiviridae family, genus Potexvirus. PepMV isolates from the same genotype differ in the symptoms they induce in Datura inoxia and Solanum lycopersicum. Necrotic isolates cause necrosis on these plants whereas mild isolates are very often asymptomatic or induce mild mosaic. Sequence analysis of the genomes of mild (PepMV-P22) and necrotic (PepMV-P19) strains revealed that they differ by several nonsynonymous mutations. Eleven mutations are located in the RdRp coding region and one mutation is placed in the TGB3 coding region. To investigate whether these mutations affect the symptom induction, both PepMV-P22 and PepMV-P19 were mutagenized. As a result we found that the genetic determinant responsible for necrosis induction was amino acid 67 of TGB3. This showed that one point mutation is sufficient to alter the virus from mild to aggressive in tomato and D. inoxia.