Global Health Institute, Ecole Polytechnique Fe´de´rale de Lausanne (EPFL), Lausanne, Switzerland.
J Bacteriol. 2011 Sep;193(18):4914-24. doi: 10.1128/JB.05396-11. Epub 2011 Jul 22.
Although it is a human pathogen, Vibrio cholerae is a regular member of aquatic habitats, such as coastal regions and estuaries. Within these environments, V. cholerae often takes advantage of the abundance of zooplankton and their chitinous molts as a nutritious surface on which the bacteria can form biofilms. Chitin also induces the developmental program of natural competence for transformation in several species of the genus Vibrio. In this study, we show that V. cholerae does not distinguish between species-specific and non-species-specific DNA at the level of DNA uptake. This is in contrast to what has been shown for other Gram-negative bacteria, such as Neisseria gonorrhoeae and Haemophilus influenzae. However, species specificity with respect to natural transformation still occurs in V. cholerae. This is based on a positive correlation between quorum sensing and natural transformation. Using mutant-strain analysis, cross-feeding experiments, and synthetic cholera autoinducer-1 (CAI-1), we provide strong evidence that the species-specific signaling molecule CAI-1 plays a major role in natural competence for transformation. We suggest that CAI-1 can be considered a competence pheromone.
虽然霍乱弧菌是人类病原体，但它也是水生栖息地（如沿海地区和河口）的常见成员。在这些环境中，霍乱弧菌通常会利用浮游动物的丰富数量及其几丁质蜕壳作为营养丰富的表面，使细菌能够形成生物膜。几丁质还会诱导几种弧菌属物种的自然转化的发育程序。在这项研究中，我们表明，在 DNA 摄取水平上，霍乱弧菌不会区分种特异性和非种特异性 DNA。这与已经证明的其他革兰氏阴性菌（如淋病奈瑟菌和流感嗜血杆菌）形成鲜明对比。然而，霍乱弧菌仍然存在针对自然转化的种特异性。这是基于群体感应和自然转化之间的正相关关系。通过突变株分析、交叉喂养实验和合成霍乱自主诱导物-1（CAI-1），我们提供了强有力的证据表明，种特异性信号分子 CAI-1 在自然转化的天然感受态中发挥主要作用。我们认为 CAI-1 可以被认为是一种感受态信息素。
