GENETIC FUNCTIONS OF A CONJUGATIVE STREPTOCOCCAL R FACTO

这项研究涉及对质粒介导的反应的详细分析， 某些粪链球菌细胞的性信息素（称为结块 诱导剂或CIA）。 拟议的研究是基于正在进行的 使用接合性、信息素响应性四环素抗性的研究 pCF-10质粒作为模型。 在拟议供资期间， 将进行三个一般类别的实验。 1)的集合 在当前资助期间获得的质粒的突变衍生物 期间将进行几个表型性状相关的分析 抗药性信息素反应和质粒转移 分子 DNA和细胞表面抗原的分析， 突变体也将进行。 2)重组DNA和转座子 诱变技术将用于确定DNA的最小量， 野生型信息素反应和质粒转移所必需的 表型。 3)野生型质粒的克隆片段的能力， 将测试互补的各种突变衍生物。 4)地区 含有重要调控和结构基因质粒将被 测序和转录这些区域的存在和 将分析不存在信息素刺激的情况：5）生物化学， 信息素诱导抗原的免疫学和功能分析将 请继续。 这种结合的方法旨在阐明遗传 控制机制和信息素反应的生物化学性质 过程 这些结果应该会提高我们对持续的 链球菌抗生素耐药性传播。 该系统也是一个 研究细胞间化学通讯的有用模型， 细菌细胞表面。

The research involves a detailed analysis of the plasmid-mediated response of certain Streptocococus faecalis cells to sex pheromones (termed clumping inducing agents, or CIAs). The proposed studies are based upon ongoing studies using a conjugative, pheromone-responsive tetracycline resistance plasmid called pCF-10 as a model. During the proposed funding period, experiments in three general categories will be done. 1) A collection of mutant derivatives of the plasmid obtained during the current funding period will be subjected to analysis of several phenotypic traits related to drug resistance, pheromone response, and plasmid transfer. Molecular analysis of the DNA and the cell surface antigens determined by these mutants will be carried out also. 2) Recombinant DNA and transposon mutagenesis techniques will be used to determine the minimum amount of DNA necessary for a wild type pheromone response and plasmid transfer phenotype. 3) The ability of cloned fragments of the wild type plasmid to compliment various mutant derivatives will be tested. 4) Regions of the plasmid that contain important regulatory and structural genes will be sequenced and the transcription of these regions in the presence and absence of pheromone stimulation will be analyzed: 5) Biochemical, immunological, and functional analyses of pheromone-induced antigens will be continued. This combined approach is designed to elucidate the genetic control mechanisms and the biochemical nature of the pheromone response process. The results should improve our understanding of the continuing spread of antibiotic resistance in streptococci. This system is also a useful model for studying intercellular chemical communication and the bacterial cell surface.