屎肠球菌BC-3产细菌素条件优化及其理化特性研究

从东北传统发酵酸菜中筛选到一株屎肠球菌BC-3,通过其代谢产生的细菌素来控制食品中的某些腐败菌和病原菌,开发其作为高效广谱食品生物防腐剂.通过滤纸片法对屎肠球菌BC-3产生细菌素发酵条件进行优化,结果表明,发酵时间为20 h、pH值为6.5、接种量为1.5％、温度为37.0℃时,抑菌圈直径最大,为17.87 mm.经硫酸铵粗提后,对肠球菌素E3生物学特性进行分析,结果表明其具有较高耐热性,在pH为2.0～10.0的范围内稳定性较好,可被蛋白酶降解,经有机溶剂处理后稳定性几乎不受影响.

EXPRESSION AND CLINICAL SIGNIFICANCE OF E2F-3 AND Bc1-2 IN HEPATOCELLULAR CARCINOMA

Objective: To investigate the expression of E2F and Bc1-2 and the clinicopathological significance in hepatocellular carcinoma. Methods: The expressions of E2F-3 and Bc1-2 in 74 patients with hepatic carcinoma, paracarcinoma and 15 patients with liver cirrhosis were detected by S-P immunohistochemical staining. Results: The expression of E2F in hepatic carcinoma was significantly higher than that in paracarcinoma or liver cirrhosis (P<0.005), the expression of Bc1-2 in hepatic carcinoma was significantly higher than that in paracarcinoma (P<0.005), in which Bc1-2 expression was lower than in liver cirrhosis(P<0.05). The expression of E2F-3 was related with histological grade, tumor size, and the expression of Bc1-2 was related with histological grade, tumor size and tumor number. There was correlation between the expression of E2F-3 and Bc1-2 in hepatic carcinoma. Conclusion: E2F-3 and Bc1-2 expression may play an important role in development, progression and cell apoptosis of tumor.

产肠球菌素乳酸菌的筛选及其生物学性质研究

从自制传统发酵酸菜中分离出34株乳酸菌，通过滤纸片法，筛选出一株对大肠杆菌有明显抑制作用的菌株屎肠球菌BC-3。其代谢产物经过排酸、排除过氧化氢后仍有抑菌活性，经过蛋白酶处理后，活性丧失，表明其产生的抑菌活性物质为细菌素。进一步对屎肠球菌BC-3产生细菌素的条件及细菌素粗提物性质进行研究，表明在37％下，培养20h，抑菌活性最高，抑菌圈直径达16．34mm。对其发酵粗提液生物学性质进行分析，结果为：肠球菌素E3具有很高的耐热性，pH2．0～10．0都具有很好的抑菌活性，金属离子、有机溶剂处理后抑菌活性几乎不受影响。