DETERMINANTS OF VIRULENCE IN BACTEROIDES FRAGILIS

脆弱拟杆菌毒力的决定因素

• 批准号: 3128852
• 负责人: FRANCIS P TALLY
• 金额: $ 15.65万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 1983
• 资助国家: 美国
• 起止时间: 1983-01-01 至 1985-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3128852
• 关键词: Bacteroides; Escherichia coli; R factors; ampicillin; bacterial DNA; bacterial genetics; chromosome translocation; erythromycin; gene expression; genetic manipulation; molecular cloning; mutant; tetracyclines; virulence

The objective of this proposal is to give a better understanding of the determinants of virulence in B. fragilis. The aspect of virulence to be investigated is the mechanism and transfer of antimicrobial resistance. Studies of antimicrobial resistance will be directed at transferable clindamycin-erythromycin, tetracycline, and ampicillin resistance. The separate functions of the clindamycin resistance (Clnr) transfer factor pBFTM10 will be analyzed. The EcoRI fragments of pBFTM10, cloned in E. coli, will be used as probes in epidemiological studies and to study transposition. The mechanism of mobilization of cryptic plasmids and Ampr by pBFTM10 will be investigated. The mechanism of clindamycin resistance encoded by pBFTM10 will be defined. The location of the tetracycline resistance (Tetr) transfer element, whether on the chromosome or a large plasmid, will be studied. The phenomenon of tetracycline induction to increased resistance transfer will be investigated. The importance of surface structures in high level Tetr transfer will be studied. Attempts will be made to transfer the Tetr element into E. coli. The location of the ampicillin resistance determinant and the mechanism of its mobilization by pBFTM10 and the Tetr transfer element will be addressed. The mechanism of cefoxitin inactivation by a clinical isolate of B. fragilis will be studied. The second aspect of the proposal is to develop a method other than conjugation to introduce plasmid and chromosomal DNA into B. fragilis. The transformation protocols developed for aerobic and facultative bacteria will be adapted to the anaerobic environment. To minimize the restriction of transforming DNA, the B. fragilis Clnr transfer factor pBFTM10 will be used. Broad host range plasmids such as RP4, which are immune to restriction systems, will also be transferred to B. fragilis for the study of chromosomal mobilization. An important consideration will be to isolate an efficient transformation recipient cell. It will be sought by obtaining mutants lacking periplasmic and/or extracellular nuclease and capsule. The results of these studies should give insight into the mechanism and transfer of resistance determinants in B. fragilis, an important virulence factor.

该提议的目的是更好地了解 脆弱芽孢杆菌中毒力的决定因素。 毒力的方面是 研究的是抗菌耐药性的机理和转移。 抗菌耐药性的研究将针对可转移 克林霉素 - 环霉素，四环素和氨苄西林耐药性。 这 克林霉素耐药性（CLNR）转移因子的单独功能 PBFTM10将进行分析。 pBftm10的Ecori片段，克隆在E中。 大肠杆菌将用作流行病学研究中的探针，并研究 换位。 动员神秘质粒的机制和 将研究PBFTM10的AMP R。 克林霉素的机制 将定义由PBFTM10编码的电阻。 位置 四环素耐药性（TER）转移元件，无论染色体上是否 或将研究大质粒。 四环素的现象 将研究增加阻力转移的诱导。 这 高水平Tetr转移中表面结构的重要性将是 研究。 将尝试将TERT元件转移到大肠杆菌中。 氨苄西林抗性决定因素的位置和机制 它通过PBFTM10的动员和Tetr传输元件将 解决。 临床分离株灭活头孢辛蛋白的机制 将研究脆弱的。 该提议的第二个方面是 开发一种除结合以外的方法来引入质粒和 染色体DNA到脆弱的芽孢杆菌中。 开发了转换协议 有氧和兼性细菌将适应厌氧菌 环境。 为了最大程度地减少转化DNA的限制，B。 将使用Fragilis CLNR转移因子PBFTM10。 广泛的主机范围 不受限制系统的RP4等质粒也将是 转移到脆弱的B. fragilis进行染色体动员研究。 一个 重要的考虑因素将是隔离有效的转换 接受者单元格。 将通过获得缺乏周质的突变体来寻求 和/或细胞外核酸酶和胶囊。 这些研究的结果 应该深入了解电阻的机制和转移 脆弱芽孢杆菌的决定因素，这是一个重要的毒力因子。