Dunn B E, Phadnis S H
Department of Pathology, Medical College of Wisconsin, Milwaukee, USA.
Yale J Biol Med. 1998 Mar-Apr;71(2):63-73.
Helicobacter pylori is the causative agent of most cases of gastritis. Once acquired, H. pylori establishes chronic persistent infection; it is this long-term infection that, is a subset of patients, leads to gastric or duodenal ulcer, gastric cancer or gastric MALT lymphoma. All fresh isolates of H. pylori express significant urease activity, which is essential to survival and pathogenesis of the bacterium. A significant fraction of urease is associated with the surface of H. pylori both in vivo and in vitro. Surface-associated urease is essential for H. pylori to resist exposure to acid in the presence of urea. The mechanism whereby urease becomes associated with the surface of H. pylori is unique. This process, which we term "altruistic autolysis," involves release of urease (and other cytoplasmic proteins) by genetically programmed autolysis with subsequent adsorption of the released urease onto the surface of neighboring intact bacteria. To our knowledge, this is the first evidence of essential communal behavior in pathogenic bacteria; such behavior is crucial to understanding the pathogenesis of H. pylori.
幽门螺杆菌是大多数胃炎病例的病原体。一旦感染，幽门螺杆菌就会建立慢性持续性感染；正是这种长期感染，在一部分患者中会导致胃溃疡、十二指肠溃疡、胃癌或胃黏膜相关淋巴组织淋巴瘤。所有新分离出的幽门螺杆菌都表现出显著的脲酶活性，这对该细菌的生存和致病机制至关重要。在体内和体外，相当一部分脲酶都与幽门螺杆菌的表面相关。表面相关脲酶对于幽门螺杆菌在有尿素存在的情况下抵抗酸暴露至关重要。脲酶与幽门螺杆菌表面结合的机制很独特。我们将这个过程称为“利他性自溶”，它涉及通过基因编程的自溶释放脲酶（和其他细胞质蛋白），随后释放的脲酶吸附到相邻完整细菌的表面。据我们所知，这是病原菌中基本群体行为的首个证据；这种行为对于理解幽门螺杆菌的致病机制至关重要。
