Evolution of Virulence in Streptococcus pneumoniae

肺炎链球菌毒力的演变

• 批准号: 7152587
• 负责人: Susan K. Hollingshead
• 金额: $ 27.89万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-12-01 至 2008-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7152587
• 关键词: Address; Alleles; Antibiotic Resistance; Antibodies; Bacteria; Colony-forming units; Communities; Complex; Country; DNA; DNA Microarray Chip; DNA Microarray format; Data; Detection; Environment; Evolution; Future; Gene Exchanges; Gene Transfer; Genes; Genetic; Genome; Genomics; Genotype; Goals; Grant; Horizontal Gene Transfer; Human; In Vitro; Individual; Intervention; Intravenous; Lateral; Length; Measures; Mind; Modeling; Molecular Epidemiology; Monoclonal Antibodies; Multi-Drug Resistance; Mus; Numbers; Polymerase Chain Reaction; Purpose; Recombinants; Recording of previous events; Sorting - Cell Movement; Streptococcus pneumoniae; Surface; Techniques; Testing; Vaccines; Variant; Virulence; Virulence Factors; Virulent; bacterial genetics; base; capsule; comparative genomic hybridization; genetic analysis; in vivo; mouse model; pneumococcal surface protein A; research study; success

Transformation has been of key importance in the history of bacterial genetics in general and streptococcal genetics in particular and it is currently still the most important technique for genetic analysis of Streptococcus pneumoniae. Transformation is the major means of spread of antibiotic resistance in this species and the factors governing transformation in natural environments will be a key factor in the success of future vaccines and interventions. The goal of this grant is to address a simple question: What is the proportion of genomic information typically exchanged during transformation in the pneumococcus? Estimates based on experiments from the 60's and 70's are that this proportion is as high as 10% of the genome but those studies were based on a small number of marker genes and the results were not representative of the whole. The readout for Igenomic exchange in our experimental approach will be the proportion of strain-specific genes exchanged las measured by microarray. In Aim 1, some of the parameters that determine this proportion during in I vitro transformation will be explored, including the length of donor DNA fragment and the concentration of donor DNA. In Aim 2, gene exchange from in vivo transformation will be followed retrospectively by looking at its extent following clonal divergence. For this purpose, the clonal complex (CC14) that includes serogroup 6 isolates in five world-wide multi drug-resistant lineages from 23 countries, will be studied. CC14 is associated with invasiveness in humans and mouse virulence vary across the lineage. Keeping in mind that virulence is multi factorial, this allows the detection of virulence-associated genes in the strain-specific gene sets. In Aim 3, in vivo transformation that has occurred during nasopharyngeal carriage in a mouse model will be examined. Isolates with recombinant genotypes will be detected by FACS sorting using markers to detect exchange in genes for two of the major virulence factors, capsule and pspA (pneumococcal surface protein A). By comparing the virulence of isolates within CC14 with their genes detected using a special microarray of strain-specific genes, we hope to also identify new virulence genes of pneumococci.

转化在整个细菌遗传学史上至关重要，并且 特别是链球菌遗传学，目前仍然是遗传的最重要技术 肺炎链球菌的分析。转化是抗生素传播的主要手段 该物种的抵抗力以及在自然环境中控制转化的因素将是关键 考虑未来疫苗和干预措施的成功。 这笔赠款的目的是解决一个简单的问题：基因组信息的比例是多少 通常在肺炎球菌转化期间交换？基于实验的估计 60年代和70年代是该比例高达基因组的10％，但这些研究是基于的。 在少量标记基因上，结果并不代表整体。读数 在我们的实验方法中，依基因组交换将是交换菌株特异性基因的比例 通过微阵列测量的LA。在AIM 1中，一些确定此比例的参数 将探索I体外转化，包括供体DNA片段的长度和浓度 供体DNA。在AIM 2中，从体内转化的基因交换将追溯到 查看克隆分歧后的程度。为此，克隆综合体（CC14） 包括来自23个国家 /地区的五个全球多种耐药谱系中的血清群6分离株，将是 研究。 CC14与人类的侵入性有关，小鼠毒力在整个谱系中各不相同。 请记住，毒力是多阶乘，这允许检测与毒力相关的基因 特异性基因集。在AIM 3中，在鼻咽期间发生的体内转化 将检查鼠标模型中的托架。通过重组基因型的分离株将被检测到 FACS使用标记物对两个主要毒力因子（胶囊）中的基因交换进行分类 和PSPA（肺炎球菌表面蛋白A）。通过比较CC14中分离株的毒力与 它们使用特殊菌株特异性基因的特殊微阵列检测到的基因，我们希望还鉴定新的基因 肺炎球菌的毒力基因。