Quorum-sensing genes in Pseudomonas aeruginosa biofilms:: Their role and expression patterns
Quorum-sensing genes in Pseudomonas aeruginosa biofilms:: Their role and expression patterns
复制标题
DOI：
10.1128/aem.67.4.1865-1873.2001
复制
发表时间：
2001-04-01
影响因子：
4.4
通讯作者：
Iglewski, BH
中科院分区：
文献类型：
--
作者：
De Kievit, TR;Gillis, R;Iglewski, BH
酰化高丝氨酸内酯分子被许多革兰氏阴性细菌用于通过称为群体感应（QS）的机制来调节细胞密度依赖性基因表达。在铜绿假单胞菌中，QS或细胞间信号传导控制许多毒力因子的表达以及生物膜分化。在这项研究中，我们研究了在静态生物膜形成的早期阶段，当细胞粘附到表面并形成小菌落时，LAS和rhL QS系统所起的作用。这些研究揭示了当葡萄糖而不是柠檬酸盐用作唯一碳源时，PAO1亲本和QS突变体之间生物膜形成的显著差异。为了进一步阐明lad和rhlI对生物膜成熟的贡献，我们利用与不稳定的绿色荧光蛋白的融合，结合共聚焦显微镜对流动环境中这些基因进行实时时空研究。在8天的生物膜发展过程中，发现lad表达随时间逐渐减少。相反，rhlI表达在整个生物膜发育过程中保持稳定，但细胞百分比较低。空间分析显示，lad和rhlI最大表达的细胞位于底层和表达随着生物膜高度的增加而下降。由于QS先前被证明参与生物膜分化，这些发现对生物膜预防和根除策略的设计具有重要意义。
Acylated homoserine lactone molecules are used by a number of gram-negative bacteria to regulate cell density-dependent gene expression by a mechanism known as quorum sensing (QS), In Pseudomonas aeruginosa, QS or cell-to cell signaling controls expression of a number of virulence factors, as well as biofilm differentiation. In this study, we investigated the role played by the las and rhl QS systems during the early stages of static biofilm formation when cells are adhering to a surface and forming microcolonies. These studies revealed a marked difference in biofilm formation between the PAO1 parent and the QS mutants when glucose, but not citrate, was used as the sole carbon source. To further elucidate the contribution of lad and rhlI to biofilm maturation, we utilized fusions to unstable green fluorescent protein in concert with confocal microscopy to perform real-time temporal and spatial studies of these genes in a flowing environment. During the course of 8-day biofilm development, lad expression was found to progressively decrease over time. Conversely, rhlI expression remained steady throughout biofilm development but occurred in a lower percentage of cells. Spatial analysis revealed that lad and rhlI were maximally expressed in cells located at the substratum and that expression decreased with increasing biofilm height. Because QS was shown previously to be involved in biofilm differentiation, these findings have important implications for the design of biofilm prevention and eradication strategies.