Expression of recombinant human acetylcholinesterase and its application in screening its inhibitors / 药学学报

This study is designed to obtain recombinant human acetylcholinesterase (rhAChE) and apply it in screening acetylcholinesterase inhibitors. The rhAChE was overexpressed in HEK293 cells transfected by plasmid of pCMV-AChE with the cationic liposome and rhAChE was found to be secreted into cell culture medium. AChE activity was assayed according to modified Ellman method to obtain kinetic parameters. IC so50 values for donepezil compounds of rhAChE were calculated to determine their activities of inhibition. The results showed that Km value was 151.9 micromol.L-1 donepezil inhibited rhAChE in a mixed competitive-noncompetitive way (Ki= 16.03 nmol.L-1, Ki = 18.36 nmol.L-1) and that most new compounds tested exhibited high activities of inhibition on rhAChE. The study suggests that rhAChE is available to be applied in screening AChE inhibitors in vitro.

Lead distribution and 78,000 glucose regulated protein levels in various organs of weaned rats / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate lead distribution and the change of 78 000 glucose regulated protein (GRP78) in various organs of weaned rats challenged with low-level maternal origin lead.</p><p><b>METHODS</b>Male littermates, bred from the female Fisher 344 rats gavaged with lead acetate or sodium acetate (1 ml of 10 mg/ml per day per animal) with male Fisher 344 rats without lead treatment, were divided into 4 groups including control (group A), gestation plus lactation (group B), gestation only (group C), and lactation only (group D). Each group had 6 litters. These littermates were weaned and terminated at postnatal day 21. Lead contents and GRP78 levels in various organs of these littermates were determined by atomic absorbance spectrometry (AAS) and Western blotting analysis, respectively.</p><p><b>RESULTS</b>Maternal lead was observed to transfer to littermates through gestation and lactation. Concentrations of littermate blood lead in groups A to D were (0.0010+/-0.0010), (0.1420+/-0.0190), (0.0250+/-0.0040), and (0.1490+/-0.0160) microg/ml, respectively. Concentrations of littermate brain lead in groups A to D were (0.0005+/-0.0005), (0.1120+/-0.0130), (0.0125+/-0.0042), and (0.0700+/-0.0058) microg/g, respectively. Concentrations of littermate kidney lead in groups A to D were (0.0050+/-0.0050), (1.0400+/-0.1000), (0.1040+/-0.0330), and (0.9920+/-0.0850) microg/g, respectively. Concentrations of littermate liver lead in groups A to D were (0.0030+/-0.0050), (0.3600+/-0.0550), (0.0567+/-0.0126), and (0.3030+/-0.0310) microg/g, respectively. Blood, brain, kidney and liver lead concentrations in groups B and D were significantly higher than those in group C and differences were 5-10 folds. Arbitrary units of littermate leukocytic GRP78 concentration normalized with actin protein in groups A to D were 1.000+/-0.038, 1.180+/-0.060, 0.998+/-0.109, and 1.290+/-0.110, respectively. Arbitrary units of littermate brain GRP78 concentration normalized with actin protein level in groups A to D were 0.996+/-0.128, 0.922+/-0.246, 1.150+/-0.170, and 0.750+/-0.126, respectively.</p><p><b>CONCLUSION</b>Lead in maternal bodies could be transferred to litter bodies through gestation and lactation and distributed in various organs. Lead might also changed GRP78 expression in leukocytes.</p>