The distribution of trypsin-like enzyme activity in cultures of a virulent and an avirulent strain of Bacteroides gingivalis W50.
The distribution of trypsin-like enzyme activity in cultures of a virulent and an avirulent strain of Bacteroides gingivalis W50.
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牙龈拟杆菌 W50 强毒株和无毒株培养物中胰蛋白酶样酶活性的分布。
DOI：
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发表时间：
1989
影响因子：
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通讯作者：
P. Marsh
中科院分区：
文献类型：
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作者：
J. Smalley;A. Birss;H. Kay;A. McKee;P. Marsh
研究了牙龈拟杆菌W50及其亲本菌株W50/BE1的无毒性变异菌株48和72 h间歇培养中胰蛋白酶样酶活性的分布。在pH 7.4条件下，用硫酸铵沉淀法回收细胞外囊泡（ECV）和可溶性细胞外蛋白（EP），测定细胞活性。两种生物都产生了细胞表面和细胞外囊泡，但菌株W50产生了更多的ECV， W50/BE1产生了更多的EP分数（按重量计）。W50全培养比W50/BE1的胰蛋白酶活性高3倍。然而，W50培养物总酶活性的90%与颗粒部分（细胞和ECV总数）有关，而该部分仅占W50/BE1总酶活性的10-30%。与W50/BE1不同，培养72 h后，W50细胞和ECV的特异性活性有所上升。相反，W50/BE1的培养能提高EP部分的产量和比活性。
The distribution of trypsin-like enzyme activity was studied in 48- and 72-h batch cultures of Bacteroides gingivalis W50 and an avirulent variant (W50/BE1) of the parent strain. Activity was measured at pH 7.4 in cells, the extracellular vesicle (ECV) and soluble extracellular protein (EP) fractions recovered by ammonium sulphate precipitation from spent growth medium. Both organisms produced cell surface and extracellular vesicles, but whilst strain W50 produced more ECV, W50/BE1 yielded more of the EP fraction by weight. Whole cultures of W50 displayed a three-fold greater trypsin activity than those of W50/BE1. However, 90% of the total enzyme activity of W50 cultures was associated with the particulate fraction (cells and ECV totalled), whereas this fraction accounted for only 10-30% of the total for W50/BE1. Unlike W50/BE1, the specific activities of W50 cells and ECV rose in 72-h cultures. Conversely, cultures of W50/BE1 displayed an increase in the yield and specific activity of the EP fraction.