从淀粉厂附近的土壤中筛选到一株能够利用淀粉的细菌,对该细菌进行生理生化检测和16S r DNA同源性比对,分析该菌株为蜡状芽孢杆菌(Bacillus cereus)。利用基因克隆技术得到了该菌株的β-淀粉酶基因,该基因含有一个约30个氨基酸的信号肽...从淀粉厂附近的土壤中筛选到一株能够利用淀粉的细菌,对该细菌进行生理生化检测和16S r DNA同源性比对,分析该菌株为蜡状芽孢杆菌(Bacillus cereus)。利用基因克隆技术得到了该菌株的β-淀粉酶基因,该基因含有一个约30个氨基酸的信号肽序列。将该β-淀粉酶基因重组进入质粒p ET-28a中,转化进入E.coli BL21(DE3)中进行表达。检测表达结果显示得到了重组后的β-淀粉酶蛋白质,重组酶的酶活力提高了53.9%。展开更多
AIM To extract and purify the transforming growth factor β (TGF β), and to demonstrate its biological activity in vivo and induction of apoptosis of hepatocytes in vitro.METHODS TGF β was isolated from fresh bovine...AIM To extract and purify the transforming growth factor β (TGF β), and to demonstrate its biological activity in vivo and induction of apoptosis of hepatocytes in vitro.METHODS TGF β was isolated from fresh bovine platelets by acid/ethanol extraction method and purified with ion exchange and gel chromatography. The extracted TGF β was injected subcutaneously to mice, and its biological activity in vivo was observed 72 hfs post-injection by HE staining. The morphological changes were observed by HE staining and the occurrence of apoptosis was detected by TUNEL method after the human normal hepatic cell line QZG was treated with 8 μg@L 1 TGFβ for 12 hrs in vitro.RESULTS The molecular mass 25 ku TGF β protein was successfully extracted. It was able to induce localized granulation tissue formation in vivo. TGF β-treated hepatocytes showed obvious apoptotic morphological changes, including the pyknosis and dense-stained nuclei and cytoplasm, the fragmentary, annular or crescent nuclei, and the "bubbling" cytoplasm. Moreover, its apoptotic rate was significantly higher than that of the control group (P＜0.05).CONCLUSION Biological active TGF β protein is extracted and purified successfully from bovine platelets, and it is able to induce the apoptosis of hepatocytes.展开更多
文摘AIM To extract and purify the transforming growth factor β (TGF β), and to demonstrate its biological activity in vivo and induction of apoptosis of hepatocytes in vitro.METHODS TGF β was isolated from fresh bovine platelets by acid/ethanol extraction method and purified with ion exchange and gel chromatography. The extracted TGF β was injected subcutaneously to mice, and its biological activity in vivo was observed 72 hfs post-injection by HE staining. The morphological changes were observed by HE staining and the occurrence of apoptosis was detected by TUNEL method after the human normal hepatic cell line QZG was treated with 8 μg@L 1 TGFβ for 12 hrs in vitro.RESULTS The molecular mass 25 ku TGF β protein was successfully extracted. It was able to induce localized granulation tissue formation in vivo. TGF β-treated hepatocytes showed obvious apoptotic morphological changes, including the pyknosis and dense-stained nuclei and cytoplasm, the fragmentary, annular or crescent nuclei, and the "bubbling" cytoplasm. Moreover, its apoptotic rate was significantly higher than that of the control group (P＜0.05).CONCLUSION Biological active TGF β protein is extracted and purified successfully from bovine platelets, and it is able to induce the apoptosis of hepatocytes.
