LYSOGENY IN ACTINOBACILLUS ACTINOMYCETEMCOMITANS

伴放线放线杆菌（Actinobacillusactinomycetemcomitans，Aalpha）是一种革兰氏阴性细菌 与几种牙周病密切相关 许多毒力因子已归因于A α 包括：白细胞毒素、内毒素、骨吸收因子、胶囊， 胶原酶、酸性和碱性磷酸酶、成纤维细胞抑制剂 因子、淋巴细胞抑制因子和免疫调节血清型- 特异性表面抗原 努力了解遗传决定因素 因为这些因素受到瞬时整合的存在的阻碍， A α中的外源遗传因子，以原噬菌体的形式存在。 当 温和的细菌病毒溶原化细菌， 经常赋予它们感染的细菌新的特性。 非常 通常，这些新特性显著增加了病原体的致病性。 宿主细胞 毒素产生、毒素释放、血清等特性 敏感性、改变的外膜结构、改变的抗原性，以及 被膜形成的改变都是由噬菌体介导的 感染 最近的研究结果表明，噬菌体感染是 在A α菌株中广泛存在。 因此，在不知道 Aalpha菌株是溶源性的，而（如果有的话）不是， 很难，如果不是不可能知道哪些毒力因子是内在的 这是因为它是一种外源性的表达， 通过病毒感染进入细胞的遗传信息。 本提案中描述的实验旨在确定 A α菌株中病毒感染的分布。 他们将 鉴定那些溶源性的A α菌株和那些 无噬菌体 因为至少有四种不同的α 已知的噬菌体，本申请中提出的方法也 旨在识别每个已知的Aalpha的分布， 溶原性A α菌株中的噬菌体。 代表性分离株 将获得每种已知的A α形态型（A，B1，B2，C）的 来自诱导的A α溶原菌。 从每种基因组制备的DNA探针 将用于筛选Aalpha菌株的DNA 与噬菌体DNA同源的序列，从而鉴定A α溶原菌。 此外，将采用固化程序来消除噬菌体 溶源性菌株的感染。 预计这些程序将导致 在确定遗传组成的A α菌株的产生中， 细菌病毒感染的术语。 这样的A α菌株将被 可供研究界确定遗传基础， 阿尔法的毒性

Actinobacillus actinomycetemcomitans (Aalpha) is a gram-negative bacterium that has been closely associated with several forms of periodontal disease in man. Numerous virulence factors have been attributed to Aalpha including: a leukotoxin, an endotoxin, a bone resorbing factor, a capsule, a collagenase, acid and alkaline phosphatases, a fibroblast inhibitory factor, a lymphocyte suppressive factor, and an immunoregulatory serotype- specific surface antigen. Efforts to understand the genetic determinants for these factors are hindered by the presence of transiently integrated exogenous genetic elements in Aalpha, in the form of prophages. When temperate bacterial viruses lysogenize bacteria, the prophages formed frequently confer new properties on the bacteria that they infect. Very often, these new properties significantly increase the pathogenicity of the host cell. Properties such as toxin production, toxin release, serum sensitivity, altered outer membrane structure, altered antigenicity, and altered capsule formation, are all known to be mediated by bacteriophage infection. Recent findings suggest that bacteriophage infection is widespread among Aalpha strains. Consequently, without knowing which Aalpha strains are lysogenic and which (if any) are not, it would be difficult, if not impossible to know which virulence factors are intrinsic to Aslpha, and which are attributable to the expression of exogenous genetic information brought into the cell by viral infection. The experiments described in this proposal are designed to determine the distribution of viral infection among strains of Aalpha. They will identify those Aalpha strains that are lysogenic and those that are bacteriophage-free. Since there are at least 4 different Aalpha bacteriophages known, the procedures proposed in this application are also directed towards identifying the distribution of each of the known Aalpha bacteriophages among the lysogenic Aalpha strains. Representative isolates of each of the known Aalpha morphotypes (A, B1, B2, C) will be obtained from induced Aalpha lysogens. DNA probes prepared from the genomes of each of the Aalpha phages will be used to screen Aalpha strains for DNA sequences homologous to the phage DNA, thereby identifying Aalpha lysogens. Furthermore, curing procedures will be employed to eliminated phage infection from lysogenic strains. These procedures are expected to result in the generation of Aalpha strains of defined genetic constitution in terms of bacterial virus infection. Such Aalpha strains will then be available to the research community for determining the genetic basis for virulence in Alpha.