The Molecular Control of Cell Death in Staphylococcus aureus

描述(由申请人提供)：这项研究的长期目标是了解细菌自溶如何有助于生物膜的形成。细菌通常以复杂的生物膜群落的形式存在于环境中。这具有临床意义，因为病原体通常在感染期间形成生物膜，并保护病原体免受免疫系统和抗生素的攻击。最近，由CIDABC和IrgAB操纵子调控的受控细胞死亡和裂解在金黄色葡萄球菌生物膜的形成中起着重要的作用。在目前的应用中，将检测这些操纵子中编码的两种蛋白质，CIDB和LrgB。这些蛋白质分布广泛，在包括细菌和古菌在内的46%的已测序基因组中发现，但没有一个具有预测或指定的功能。这一应用的具体目的是：1)使用细胞存活和自溶、抗生素耐受性和生物膜产生的分析来表征编码这些蛋白质的基因的突变；以及2)检查可能对功能重要的细胞定位和蛋白质-蛋白质相互作用。这项研究中概述的实验结果将检验两种以前未确定的蛋白质的功能，它们被认为参与控制细胞死亡和裂解。这将提供对细菌中鲜为人知的程序性细胞死亡过程的洞察，以及这一过程如何有助于生物膜的建立。最后，它可能为新型抗菌剂的开发提供新的途径。公共卫生相关性：细菌感染对世界各地的人类健康构成越来越大的威胁，主要是因为它们越来越有能力导致对抗生素治疗抗拒的感染。本申请中描述的研究重点是细菌作为复杂发育过程的一部分来调节自己的细胞死亡这一新概念。这些研究的结果将提供更好的了解控制细菌细胞死亡的分子机制，并将导致新的和更有效的治疗策略来对抗感染。

DESCRIPTION (provided by applicant): The long-term goal of this research is to understand how bacterial autolysis contributes to biofilm formation. Bacteria are commonly found in the environment as complex biofilm communities. This has clinical significance as pathogens often form biofilms during infection and protect the pathogen from the immune system and antibiotics. Recently, controlled cell death and lysis modulated by the cidABC and IrgAB operons have been shown to be important in Staphylococcus aureus biofilm formation. In the current application, two of the proteins encoded in these operons, CidB and LrgB, will be examined. These proteins are wide-spread, being found in 46 percent of sequenced genomes including bacteria and archaea, yet none have a predicted or assigned function. The specific aims of this application are to: 1) characterize mutants in the genes encoding these proteins using assays of cell survival and autolysis, antibiotic tolerance, and biofilm production; and, 2) examine the cellular localization and protein-protein interactions that may be important for function. The results of the experiments outlined in this study will examine the function of two previously uncharacterized proteins believed to be involved in controlling cell death and lysis. This will provide insight into the poorly understood process of programmed cell death in bacteria and how this process contributes to the establishment of a biofilm. Finally, it may suggest new avenues to pursue for the development of novel antibacterial agents. PUBLIC HEALTH RELEVANCE: Bacterial infections are a growing threat to human health around the world primarily due to their increasing ability to cause infections recalcitrant to antibiotic therapy. The research described in this application focuses on the novel concept that bacteria regulate their own cell death as part of complex developmental processes. The results generated by these studies will provide a better understanding of the molecular mechanisms controlling bacterial cell death and will lead to novel and more effective therapeutic strategies to combat infections.