竹纤维生物酶脱胶技术初探

本文主要研究生物酶处理对竹纤维脱胶效果的影响.采用正交实验优化半纤维素酶脱胶处理的工艺条件,测试了处理后竹纤维的重量损失、残胶率等.实验结果表明,当温度为65℃,半纤维素酶用量为0.10g/ml,pH值在8.0附近,处理时间为180min时竹纤维能获得相对较好的脱胶效果.重量损失在8%左右.残胶率为32.7%,减少了45.05%.     

柑橘精油研究进展

JIN jia-jia;WEI jie(College of Agriculture, Guangxi University, Nanning 530000, China)     

Electrophysiological characteristics of the membrane current of cardiomyocytes-like cells derived from rat bone marrow mesenchymal stem cells

AIM: To study the electrophysiological characteristics of the membrane currents of cardiomyocytes-like cells derived from rat bone marrow mesenchymal stem cells (MSCs).METHODS: MSCs were induced,cultured and identified according to the reference.At the fourth week after treatment with 5-azacytidine(5-aza),cardiomyocytes-like cells were detected for the membrane current with the whole-cell patch-clamp technique and compared with the undifferentiated MSCs.RESULTS: The undifferentiated MSCs only expressed potassium currents.MSCs were stained positive for troponin T after treatment with 5-aza,and two kinds of inward currents and three kinds of outward currents were expressed.They respectively were the fast inward sodium current (I_Na),the L-type calcium current (I_Ca),the transient outward potassium current (I_to),the ultra-rapid delayed rectifier potassium current (I_kur) and the slow delayed rectifier potassium current (I_ks).Compared with the undifferentiated MSCs,the potassium currents of cardiomyocytes-like cells derived from MSCs were mainly made up of I_kur and I_ks.CONCLUSION: After treatment with 5-azacytidine,MSCs are differentiated into cardiomyocytes-like cells,which express the current of I_Na,I_Ca,I_to,I_kur and I_ks.     

Study on Cx43 communication function of cardiomyocyte-like cells derived from rat bone marrow mesenchymal stem cells in vitro

AIM: To approach the gap junction distribution and communication function of cardiomyocyte-like cells derived from rat bone marrow mesenchymal stem cells (MSCs) in vitro.METHODS: MSCs were isolated by extraction of bone marrow specimens,gradient centrifugation and the adherence of culture plates.MSCs were culture in vitro,treated with 5-azacytidine and incubated for 24 h.The induced MSCs,which had been incubated for 2,3 and 4 weeks,were divided into group Ⅰ,Ⅱ and Ⅲ.In addition,the normal cardiomyocyte cells were used as control group.The distribution of connexin 43(Cx43) and the mean fluorescence redistribution rate were detected in every group with the laser scanning confocal microscope.RESULTS: Cx43 protein grain density in induced MSCs was increased with the lasting of incubation by quantitive analysis of Cx43 distribution.After 4 weeks,the Cx43 protein density in induced MSCs was nonsignificant deviation with control group (63.87±12.43,64.87±12.15,P>0.05).The diversify tendency of the mean fluorescence redistribution rate was approximation with the result of Cx43 in every group.The results showed that groupⅠ was 19.59%±6.08%,groupⅡ was 37.17%±3.84%,groupⅢ was 46.82%±2.69%,and control group was 49.71%±5.53%.CONCLUSION: MSCs can be differentiated to cardiomyocyte-like cells,which have been induced and incubated for 4 weeks in vitro.The communicational function of those MSCs is similar to the normal cardiomyocyte cells.