Eukaryotic Perception of Prokaryotic Quorum Signals

描述（由申请人提供）：许多细菌调节毒力因子表达，作为其种群密度的函数。这种现象被称为“群体感应”（QS），是由各种小分子的检测驱动的，这些小分子统称为“自诱导物”（Als）。最佳表征的Al是革兰氏阴性菌利用的N-酰化L-高丝氨酸内酯（AHLs）。操纵AHLs来调节毒力因子的表达，而不对病原体施加选择压力，是一种有吸引力的抗菌策略，已获得相当大的关注。然而，由于细菌之间发生这些“化学对话”的真核生物表面也对这些信号敏感，因此了解真核生物对AHLs的反应对于开发这种新的治疗策略至关重要。我建议开发植物作为一个模型系统，用于定义真核反应的AHLs由于不同的阵列的突变体和报告结构，它们相对容易的遗传操作，快速的生长速度，和明确的生理，以及它们的能力，以检测和响应AHLs。在开发这个模型时，我打算利用组合合成的最新进展，这些进展导致了阿勒类似物（“200种化合物”）的相当大的库的开发。将在烟草、苜蓿和白色三叶草等模式植物系统中筛选该文库，以鉴定在多个时间点对各种结构不同的AHL的关键激素和生理反应。将通过基于细胞的（原生质体）试验以及荧光显微镜检查评价阿勒反应。这种双重方法允许高通量筛选以及组织定位。进一步的研究将评估选择AHLs的感知如何影响植物根系分泌物的QS调节活性。这些研究的结果将在其对QS调节作为调节细菌毒力的新策略的发展的潜在影响的背景下进行评估。公共卫生相关性：大多数人类感染依赖于细菌之间交换的复杂的“化学对话”。围绕这些信号的破坏而设计的新的抗菌策略目前正在开发中，并有望对人类健康产生重大影响。然而，了解宿主生物体对这些细菌信号的反应对于开发信号破坏作为一种新的抗菌策略至关重要。

DESCRIPTION (provided by applicant): Many bacteria regulate virulence factor expression as a function of their population density. This phenomenon, known as 'quorum sensing' (QS), is driven by the detection of a variety of small molecules, collectively referred to as 'autoinducers' (Als). The best characterized Als are the N-acylated L-homoserine lactones (AHLs) utilized by Gram-negative bacteria. The manipulation of AHLs to regulate virulencefactor expression, without exerting selection pressures on the pathogen, is an attractive antimicrobial strategy that has gained considerable attention. However, as the eukaryotic surfaces at which these 'chemical dialogues' between bacteria occurs are also sensitive to these signals, understanding the responses of eukaryotes to AHLs is critical to developing such novel therapeutic strategies. I propose to develop plants as a model system for defining eukaryotic responses to AHLs due to the diverse array of mutants and reporter constructs that are available, their relative ease of genetic manipulation, rapid growth rates, and well defined physiology, as well as their ability to detect and respond to AHLs. In developing this model I intend to exploit recent advances in combinatorial synthesis that have led to the development of a sizeable library of AHL analogues (" 200 compounds). This library will be screened in model plant systems like tobacco, alfalfa, and white clover to identify critical hormonal and physiological responses to a variety of structurally distinct AHLs at multiple time points. AHL responses will be evaluated by both cell-based (protoplast) assays as well as fluorescence microscopy. This two-fold approach permits both high throughput screening as well as tissue localization. Additional studies will evaluate how the perception of select AHLs affects the QS regulatory activity of the root exudate of plants. The results of these studies will be evaluated within the context of their potential impact to the development of QS-regulation as a novel strategy for regulating virulence in bacteria. PUBLIC HEALTH RELEVANCE: The majority of human infections are dependent on a complex 'chemical dialogue' exchanged between bacteria. New antimicrobial strategies, designed around the disruption of these signals, are currently under development and promise to have a substantial impact on human health. However, understanding the responses of host organisms to these bacterial signals is crucial in developing signal disruption as a novel antimicrobial strategy.