Construction of rice stripe virus NS2 and NS3 Co-RNAi transgenic rice and disease-resistance analysis / 病毒学报

NS2 and NS3 are two post-transcriptional gene silencing suppressors that are encoded by Rice stripe virus. Gene silencing suppressors are always related to the pathogenicity of viruses. In this study, the cDNA of NS2 and NS3 were recombined by overlapping PCR assays, ligated to the RNAi vector, and inserted into the PXQ expression vector using Pst I; the expressed vector was transferred into calluses induced from seeds of the japonica rice cultivar, 'Nipponbare', using an Agrobacterium-mediated method. Thirty-one T0 transgenic plants were selected by G418 screening. PCR and southern blot analyses confirmed that the target gene was transformed into transgenic rice successfully, and different transgenic plants contained various copies of the gene. The disease resistance assay revealed that T0 transgenic rice had a delayed onset of RSV for approximately 10-20 d, and the accumulation of virus in the transgenic plants was reduced by 30%-50%. This was related to the delayed onset of disease.

Analysis of isorhamnetin-3-O-neohesperidoside in rat plasma by liquid chromatography/electrospray ionization tandem mass spectrometry and its application to pharmacokinetic studies / 中国天然药物

AIM@#To establish an LC-MS/MS method for determination of isorhamnetin-3-O-neohesperidoside and investigate its application on pharmacokinetic study in rats.@*METHODS@#Eight rats were given 5 mg·kg(-1) isorhamnetin-3-O-neohesperidoside after intravenous administration. A highly sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of isorhamnetin-3-O-neohesperidosidein rat plasma using rutin as internal standard. The analytes and rutin (internal standard) were extracted with methanol followed by a rapid isocratic elution with 10 mmol·L(-1) ammonium acetate buffer/methanol (20 : 80, V/V) on a C18 column (150 mm × 2.1 mm, I.D., 5 μm) and subsequent analysis by mass spectrometry in the multi-eaction-monitoring mode.@*RESULTS@#The assays were linear over the concentration range of 0.01-10 μg·mL(-1) for isorhamnetin-3-O-neohesperidosidein rat plasma. The lower limit of quantifications for isorhamnetin-3-O-neohesperidoside was 0.01 μg·mL(-1).@*CONCLUSION@#The validated method is successfully applied to determine the plasma concentrations of isorhamnetin-3-O-neohesperidosidein in rats.