A novel peptide from alpha5 helix of Asterina pectinifera cyclin B conjugated to HIV-Tat(49-57) with cytotoxic and apoptotic effects against human cancer cells

A series of novel peptides from various motifs of Asterina pectinifera cyclin B and their derivatives conjugated to HIV-Tat(49-57) were designed and synthesized. Their bioactivities on two human cancer cell lines were determined. Among them, Tat-a5 (KAQIRAMECNILGRKKRRQRRR) exhibited significant cytotoxic effects on cancer cell lines EC-9706 and HCT-116. Tat-a5 could arrest cancer cells at G(2)/M phase and make them apoptotic. Our results suggested that Tat-a5 could be a novel leading peptide with anticancer activity.     

Facile synthesis of novel mutual derivatives of nucleosides and pyrimidines by regioselectively chemo-enzymatic protocol

We established a facile regioselectively chemo-enzymatic synthesis procedure for the preparation of mutual derivatives of nucleosides and pyrimidines by sequential Markovnikov addition and acylation. Firstly, pyrimidine derivatives containing vinyl ester group were synthesized from pyrimidines and divinyl esters through Markovnikov addition catalyzed by K₂CO₃ in DMSO at 80 °C, and the yields were ranged from 50% to 87%. Then regioselective acylation of ribavirin and cytarabine with pyrimidine vinyl ester was catalyzed by CAL-B (immobilized lipase from Candida antarctica) in anhydrous acetone. Reaction conditions of enzymatic acylation including enzyme resource and solvents were optimized. A series of mutual derivatives of nucleosides and pyrimidines were synthesized successfully and characterized with NMR, IR, and HRMS. This chemo-enzymatic protocol involving sequential Markovnikov addition and acylation provided a novel way of synthesizing complicated functional compounds regioselectively which was hard to be achieved either by chemical or by enzymatic methods.     

Stereoselective degradation of benalaxyl in tomato, tobacco, sugar beet, capsicum, and soil

The stereoselective degradation of the racemic benalaxyl in vegetables such as tomato, tobacco, sugar beet, capsicum, and the soil has been investigated. The two enantiomers of benalaxyl in the matrix were extracted by organic solvent and determined by validated chiral high-performance liquid chromatography with a cellulose-tris-(3, 5-dimethylphenylcarbamate)-based chiral column. Rac-benalaxyl was fortified into the soil and foliar applied to vegetables. The assay method was linear over a range of concentrations (0.5-50 microg ml(-1)) and the mean recoveries in all the samples were more than 70% for the two enantiomers. The limit of detection for both enantiomers was 0.05 microg g(-1). The results in soil showed that R-(-)-enantiomer dissipated faster than S-(+)-enantiomer and the stereoselectivity might be caused by microorganisms. In tomato, tobacco, sugar, beet, and capsicum plants, there was significantly stereoselective metabolism. The preferential absorption and degradation of S-(+)-enantiomer resulted an enrichment of the R-(-)-enantiomer residue in all the vegetables.     

Combination of Dexamethasone and Aminoguanidine Reduces Secondary Damage in Compression Spinal Cord Injury

The study was performed to investigate the effect of combination therapy with aminoguanidine (AG) and dexamethasone (DEX) on the compression spinal cord injury (SCI) in rat. Compared to the control group, the combination therapy group with AG (75 mg/kg) and DEX (0.025 mg/kg) significantly reduced the degree of (1) spinal cord edema, (2) the permeability of blood spinal cord barrier (measured by ^99mTc-Albumin), (3) infiltration of neutrophils (MPO evaluation), (4) cytokines expression (tumor necrosis factor-α and interleukin-1β), and (5) apoptosis (measured by Bax and Bcl-2 expression). In addition, we have also clearly demonstrated that the combination therapy significantly ameliorated the recovery of limb function (evaluated by motor recovery score). Taken together, our results clearly indicated for the first time that strategies targeting multiple proinflammatory pathways may be more effective than a single effector molecule for the treatment of SCI.