Assigning function of unknown genes of Acinetobacter baumanii by cell envelope

该建议将定义革兰氏阴性菌不动杆菌的未知功能基因（GUF 鲍曼不动杆菌（Ab），其有助于细胞包膜的结构和屏障功能。革兰氏阴性 细菌被膜是一种有序的大分子复合物，其独特之处在于由两个 膜。外膜（OM）是由不对称双层组成的独特结构， 脂多糖（LPS）（外叶）和甘油磷脂（内叶），形成了第一条线， 通过作为渗透屏障来防御防腐剂和抗菌剂。Ab有一种新的细胞 抗生素相对不可渗透的包膜，并且已经分离出不能渗透的粘菌素抗性Ab， 合成LPS。这些新的性质表明，抗体的研究 信封应该揭示临床相关性的重要新知识。我们的初步数据和公布的 对Ab LPS无效突变体的转录谱的研究导致了生物信息学分析和选择 - 一组Ab GUF，其是参与维持受调节的渗透性屏障的候选者。 这些GUF将通过构建突变株来表征，所述突变株将被分析用于改变 化学探针的渗透性。具有改变的包膜渗透性的菌株将受到敏感性 抗微生物肽和抗生素的测试，磷脂和脂质A的化学分析，以及，当 适当的，在疾病的动物模型中测试。在迭代过程中，为 在未来几年的表征中，我们将使用基于FACS的细胞分选进行特定的遗传筛选， 药物和温度敏感性筛选，以鉴定有助于细胞包膜结构的GUF， 功能最后，我们将整合来自Manoil和Harwood博士项目的数据， 布鲁斯博士的技术核心，以定义用于表征的附加GUF。这项提案将考验 调节革兰氏阴性包膜未发现的结构改变的假说， GUF是病原体防御宿主先天免疫、抗菌和消毒的组成部分 攻击

This proposal will define genes of unknown function (GUF) of the Gram-negative bacteria Acinetobacter baumannii (Ab) that contribute to the structure and barrier function of the cell envelope. The Gram-negative bacterial envelope is an ordered complex of macromolecules that is unique in being comprised of two membranes. The outer membrane (OM), a unique structure composed of an asymmetrical bilayer consisting of lipopolysaccharide (LPS) (outer leaflet) and glycerophospholipids (inner leaflet), forms the first line of defense against antiseptics and antimicrobials by functioning as a permeability barrier. Ab has a novel cell envelope that is relatively impermeable to antibiotics, and colistin resistant Ab have been isolated that cannot synthesize LPS from patients treated with colistin. These novel properties suggest that the study of the Ab envelope should reveal important new knowledge of clinical relevance. Our preliminary data and published studies of transcriptional profiles of the Ab LPS null mutant have led to bioinformatics analysis and selection o f a set of Ab GUF that are candidates for participation in maintenance o f a regulated permeability barrier. These GUF will be characterized by construction of mutant strains that will be analyzed for altered permeability to chemical probes. Strains with altered envelope permeability will be subjected to susceptibility testing to antimicrobial peptides and antibiotics, chemical analysis of phospholipids and lipid A, and, when appropriate, testing in animal models of disease. In an iterative process to define new GUF for characterization in further years, we will employ specific genetic screens using FACS-based cell sorting, drug, and temperature sensitivity screens to identify GUF that contribute to cell envelope structure and function. Lastly, we will integrate data from the projects of Drs. Manoil and Harwood and utilize the technological core of Dr. Bruce to define additional GUF for characterization. This proposal will test the hypothesis that regulated undiscovered structural alterations of the Gram-negative envelope encoded by GUF are a component of pathogen defense against host innate immune, antimicrobial, and disinfectant attack.