Abstract A chiral separation and residue determination method for cis-epoxiconazole enantiomers in apple, grape and tea samples was developed and validated by ultra performance convergence chromatography combined with quadrupole time-of-flight mass spectrometry ( UPC2-QTOF/MS) . The Chrial CCA column was used to separate cis-epoxiconazole enantiomers and the chromatography conditions ( mobile phase modifier and proportion, column temperature, automated backpressure regulator, and auxiliary solvent ) were optimized. Samples were extracted by acetonitrile, and respectively purified by Cleanert TPT or Pesti-Carb solid phase extraction ( SPE ) columns, then analyzed by UPC2-QTOF/MS. The optimum conditions were as follows:mobile phase was CO2/isopropanol (95: 5, V/V), flow-rate was 2. 0 mL/min, automated backpressure regulator (ABPR) was 13. 79 MPa, column temperature was 30℃, with a post-column mauxiliary solvent of methanol/water (1:1, V/V) containing 2 mmol/L ammonium formate. The analyte was quantified by matrix external standard method. The results showed that linear range of this method was 0. 01-1. 00 mg/L, and the correlation coefficients were above 0 . 99 . The recoveries of cis-epoxiconazole enantiomers at three spiked levels (0. 005, 0. 025 and 0. 25 mg/kg) in fruit matrix were 67. 9%-92. 8% with relative standard deviations (RSDs, n=6) less than 10%, and the limit of quantification (LOQ) of enantiomers was 0. 005 mg/kg. The recoveries of cis-epoxiconazole enantiomers at three spiked levels (0. 01, 0. 05 and 0. 5 mg/kg) in black tea were 74 . 1% -84 . 0% with RSDs ( n=6 ) less than 8%, and the LOQ for these two enantiomers was 0. 01 mg/kg. This method is rapid, convenient and reliable, and could meet the requirement of residue analysis.

OBJECTIVETo clone and characterize the DNA and cDNA sequences of phenylalanine ammonia-lyase gene (PAL) from Fagopyrum dibotrys, and investigate the biological activity of the obtained PAL.

METHODUsing homology cloning and RT-PCR techniques, the DNA and full-length cDNA sequences of PAL gene were amplified from F. dibotrys. The obtained sequences were analyzed by bioinformatics software. The ORF of PAL gene was cloned into expression vector pET-30b(+) and transformed into Escherichia coli BL21 (DE3) for expression the recombined protein. The catalytic activity of the recombined protein was determined by Spectrophotometer and thin layer chromatography (TLC) methods.

RESULTThe DNA sequence of PAL gene (designated as FdPAL, GenBank accession number: HM628904) was 2 583 bp in size, of which consisted two extrons and a single intron, and the full-length cDNA of FdPAL was 2 169 bp in size, which contained an ORF. The deduced protein of FdPAL contained 722 amino acids with calculated molecular weight (MW) of 78.31 kDa and an isoelectric point (pI) of 5.94. The SDS-PAGE results showed that the molecular weight of recombinant FdPAL protein was 75.37 kDa, which is consistent with the predictions. After 4 hours of induction, the enzymatic specific activity of FdPAL reached the summit, up to 4 386 nmol x g(-1) x min(-1). The reaction products were also identified by TLC, using L-Phe and trans-cinnamic acid as the internal standard.

CONCLUSIONThe PAL gene (both DNA sequence and full-length cDNA sequence) was cloned from F. dibotrys, and it has the same classic characters as other PALs in plants. The recombinant FdPAL was efficiently expressed in E. coli and had the activity for catalyzing the conversion from L-phenylalanine to cinnamic acid.

Amino Acid Sequence ; Base Sequence ; Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Fagopyrum ; classification ; genetics ; Molecular Sequence Data ; Phenylalanine Ammonia-Lyase ; chemistry ; genetics ; metabolism ; Phylogeny ; Protein Conformation ; Recombinant Proteins ; chemistry ; genetics ; metabolism

The occurrence of thyroid gland is easily affected by iodine deficiency, the enzyme defect, drugs, autoimmune and other factors. The increased incidence of thyroid cancer year by year has threatened the health of the human, which requires to study thyroid gland cancer invasion and metastasis, investigate the molecular mechanism of cancer metastasis, search the differential molecular expression gene, predict the metastatic biomarkers and the intervening treatment target molecule, in order to improve the cure rate and the survival rate. This paper reviews the possible role of long chain non-coding RP11-23J9.4-miRNA-15a-axis inhibiting factor 2-Wnt pathway in the occurrence, development and dedifferentiation of thyroid cancer.

Ferroptosis is a newly discovered form of cell death in recent years. Its essence is the cell peroxidation death caused by the accumulation of intracellular lipid reactive oxygen species (L-ROS) in a iron-dependent manner. As a highly efficient ferroptosis inducer, Erastin mediates ferroptosis through multiple molecules, such as cystine-glutamate transport receptor, voltage-dependent anion channel and p53. More importantly, Erastin can enhance the sensitivity of cancer cells to chemotherapy and radiotherapy, so it can be used as a new type of anticancer drug. This article reviews the discovery of Erastin, the pathways of ferroptosis, the pathways of Erastin-induced ferroptosis, the anti-tumor characteristics of Erastin, and the latest domestic and international research results.