Schraw W, McClain M S, Cover T L
Division of Infectious Diseases, Department of Medicine, Nashville, Tennessee 37232-2605, USA.
Infect Immun. 1999 Oct;67(10):5247-52. doi: 10.1128/IAI.67.10.5247-5252.1999.
To investigate the kinetics and mechanisms of extracellular protein release by Helicobacter pylori, we analyzed the entry of metabolically radiolabeled bacterial proteins into broth culture supernatant. At early time points, vacuolating cytotoxin (VacA) constituted a major extracellular protein. Subsequently, culture supernatants accumulated many proteins that were components of intact bacterial cells. This nonselective release of proteins was associated with a decreasing turbidity of cultures and loss of bacterial viability, indicative of an autolytic process. The rates of VacA secretion and autolysis were each influenced by medium composition, and therefore these may be regulated phenomena. Extracellular release of proteins by H. pylori may be an important adaptation that facilitates the persistence of H. pylori in the human gastric mucus layer. Moreover, entry of proinflammatory proteins into the gastric mucosa may contribute to the induction of a mucosal inflammatory response.
为了研究幽门螺杆菌释放细胞外蛋白质的动力学和机制，我们分析了经代谢放射性标记的细菌蛋白质进入肉汤培养上清液的情况。在早期时间点，空泡毒素（VacA）是主要的细胞外蛋白质。随后，培养上清液中积累了许多完整细菌细胞的组成蛋白。这种蛋白质的非选择性释放与培养物浊度降低和细菌活力丧失有关，表明这是一个自溶过程。VacA分泌和自溶的速率均受培养基成分影响，因此这些可能是受调控的现象。幽门螺杆菌释放蛋白质到细胞外可能是一种重要的适应性变化，有助于幽门螺杆菌在人胃黏液层中持续存在。此外，促炎蛋白进入胃黏膜可能有助于诱导黏膜炎症反应。
