Purification and Identification of Recombinant Alpha-bungarotoxin

[ Objective ] This paper aimed to obtain active alpha-bungarotoxin （α-BGT） protein and investigate the isolation and purification of recombinant α-BGT protein. [ Method] The expressed soluble fusion protein was purified by using GSTrap FF affinity columns. Purified fusion protein bound to GSTrap FF affinity col- umns was directly cleaved by thrombin to obtain the solution containing recombinant α-BGT. Using natural α-BGT as control, the antigenicity and biological activity of the purified fusion protein and recombinant α-BGT were detected by SDS-PAGE, Western Blot and toxicity test in vivo. [ Result] Recombinant ot-BGT was iso- lated; the purified fusion protein and recombinant α-BGT were similar to the natural α-BGT in antigenicity; the toxicity of purified fusion protein was relatively wea- ker; recombinant α-BGT was similar to the natural ot-BGT in toxicity. [Condusion] This study laid the foundation for further large-scale production of recombi- nant α-BGT.

New Insight into Microvascular Perfusion by Analyzing Pipe Flow in a Cylindrical Elastic Shell

Background: Microvascular perfusion, a kind of regional perfusion, plays important roles in delivering oxygen and nutrients, and regulating blood pressure and responses to inflammation. Aim: The aim of this research is to analyze the characteristics of microvascular perfusion by conducting pipe flow in a circular elastic tube. Methods: A model was established with circular elastic tube to mimic microvascular perfusion. The velocity of pressure waves was calculated according to the time that the liquid took to spilt over. What’s more, the characteristics and significance of microvascular flow and arteriovenous anastomoses (AVAs) were analyzed. Results: It took the liquid about 0.1 second to spill over from the model, and the velocity of pressure waves is greater than 100 m/s in the elastic pipe. A mechanical switch structure and the corresponding mechanism were proposed for microvascular perfusion in AVAs. Conclusion: Microvascular perfusion maintains a considerable constancy of hemodynamics in different tissues, when ventricular contraction changes perfusion pressure to meet metabolic demands appropriately. This theory will help us to gain a new perspective in microvascular flow.

Embryotoxicity and Teratogenicity of Rhein

To study the effect ofrhein on embryo development of rats and fetuscs, the SD rats were divided into rhein （87.5, 175 and 350 mg/kg） group and negative control group treated with 0.5% CMC （carboxyl methyl cellulose）. The rats were administrated with rhein daily for 10 days from 6th to 15th day after pregnancy. The pregnancy rats were dissected at 20th day after pregnancy. The total weight of the fetuses, the number of corpus luteum, plant gland, absorbed fetus, live fetus, dead futus, monsters, body weight, body height and tail length were recorded. Compared with the control group, rhein group occurred with the administration of toxicity-related clinical symptoms. The changes in weight increase related with the amount ofrhein （P 〈 0.05） and the increased number of absorbed fetuses in each rhein group （P 〈 0.05） were presented. Obvious differences occurred in the rhein groups in terms of the incidence of visceral abnormalities, each organ abnormalities and fossa malformations, etc. （P 〈 0.05）. Compared with the control group, there was no significant difference in the low-dose group by fetal rat bone examination （P 〉 0.05）, while the remaining dose groups manifested various bone deformities such as sternum sections missing, incomplete ossification of the skull and thoracic vertebrae separation or deformation, which was obviously different from the control group （P 〈 0.01）. Rhein had a significant effect on the reproductive function of pregnant rats. It can even result in the bones＇ and internal organs＇ dysplasia of fetal rats. Rhein has a significant teratogenic effect in rats.