植物青枯菌细菌素的纯化及其性质的研究

PURIFICATION AND SOME PROPERTIES OF BACTERIOCIN PRODUCED BY PSEUDOMONAS SOLANACEARUM

植物青枯菌菌株M2在牛肉汁蛋白陈培养液中产生的细菌素经过硫酸铵沉淀和阴离子纤维素交换柱DE-52分离后,在聚丙烯酰胺凝胶电泳时,呈现1条蛋白带。该蛋白带经电泳法回收后具有细菌素活性;该细菌素命名为solanacearicin M2,它在SDS-聚丙烯酰胺凝胶电泳时呈现2条带。看来,solanacearicin M2是由这两个亚基组成,两亚基的分子量分別约为68000和70000。Solanacearicin M2对proteinase、pronase E、trypsin等蛋白酶敏感,对RNase和DNase不敏感;在60℃以下处理10mia,细菌素活性稳定,在室温下存放15天或4℃存放90天仍保持细菌素活性,在65℃处理10min便失去细菌素活性。用来自马铃薯、花生和甘薯上的17株菌作为指示菌,检测了另外17株青枯菌产生的细菌素;采用Eckhardt法和改良的Kado法检测了这些细菌素产生菌的内生质粒。结果表明,青枯菌致病性菌株与它们衍生的相应的非致病性菌株所产生的细菌素具有相同的抑菌谱和抑菌强度,青枯菌细菌素的产生与其致病性之间没有相关性;B2、AM2、AP7、M2和P7等菌株产生的细菌素不是由质粒编码的。

The bacteriocin from strain M2 of Pseudomonas solanacearum was purified by ammonium sulphate precipitation and anion exchange chromatography. This bacteriocin was designated as solanacearicin M2, which appeared as one band on polyacrylamide gels. The bacteriocin showed antagonistic activity when it was recovered from the band through electrophoresis. Solanacearicin M2 was sensitive to proteinase, pronase E and trypsin, but insensitive to RNase and DNase. As determined by SDS-PAGE, solanacearicin M2 consisted of two subunits with molecular weight of about 68 000 and 70 000. The bacteriocin present in pH7.3, 0.05mol/L KH_2PO_4·K_2HPO_4 buffer was stable for fifteen days at room temperature and for ninty days at 4℃. The solanacearicin M2 was inactivated after treatment at 65℃ for ten minutes.