Graduate School of Life and Environmental Sciences, University of Tsukuba, 1–1–1 Tennodai, Tsukuba, Ibaraki 305–8572, Japan.
Microbes Environ. 2010;25(2):120-5. doi: 10.1264/jsme2.me09182.
Many Gram-negative bacteria naturally produce membrane vesicles (MVs) to the extracellular milieu. The Pseudomonas quinolone signal (PQS), a quorum-sensing signal of Pseudomonas aeruginosa, is a positive regulator of MV production. In this study, we investigated its effects on MV production in other Gram-negative and -positive bacterial species. The addition of PQS to an Escherichia coli K12 culture resulted in increased MV production and enlarged MVs. An excessive amount of MgCl(2) repressed E. coli MV production either with or without PQS, suggesting that an anionic repulsion of cellular surfaces increases MV production. PQS was found in the cellular membrane and MVs in E. coli. The enhancement of MV production by PQS occurred in other Gram-negative bacteria, including Burkholderia and Pseudomonas species. Moreover, PQS induced MV production in a Gram-positive bacterium, Bacillus subtilis 168, which does not normally produce MV under laboratory conditions. An excessive amount of MgCl(2) did not repress B. subtilis MV production in the presence of PQS, suggesting the production mechanism to be different from that in Gram-negative bacteria. Together, these results indicated that PQS enhances MV production in Gram-negative bacteria and induces it in Gram-positive bacteria.
许多革兰氏阴性菌自然会向细胞外环境产生膜泡（MVs）。铜绿假单胞菌群体感应信号（PQS）是铜绿假单胞菌的群体感应信号，是 MV 产生的正调节剂。在这项研究中，我们研究了它对其他革兰氏阴性和阳性细菌物种中 MV 产生的影响。向大肠杆菌 K12 培养物中添加 PQS 会导致 MV 产生增加和 MV 增大。过量的 MgCl2 抑制了有无 PQS 的大肠杆菌 MV 产生，这表明细胞表面的阴离子排斥会增加 MV 产生。在大肠杆菌中，PQS 存在于细胞膜和 MV 中。PQS 在其他革兰氏阴性菌，包括伯克霍尔德菌和假单胞菌属中增强了 MV 的产生。此外，PQS 诱导了革兰氏阳性菌枯草芽孢杆菌 168 的 MV 产生，而在实验室条件下，枯草芽孢杆菌通常不会产生 MV。过量的 MgCl2 不会抑制有 PQS 存在时枯草芽孢杆菌的 MV 产生，这表明其产生机制与革兰氏阴性菌不同。总之，这些结果表明 PQS 增强了革兰氏阴性菌中的 MV 产生，并诱导了革兰氏阳性菌中的 MV 产生。
