CELL-CELL INTERACTION BETWEEN ORAL ACTINOMYCETES AND OTHER ORAL BACTERIA

口腔放线菌和其他口腔细菌之间的细胞间相互作用

• 批准号: 5201761
• 负责人: P E KOLENBRANDER
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF DENTAL & CRANIOFACIAL RESEARCH
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/5201761
• 关键词: Actinomycetales; adhesin; bacterial genetics; binding proteins; cell cell interaction; ecology; genetic strain; lactose; molecular cloning; molecular pathology; mutant; nucleic acid sequence; operon; oral bacteria; phenotype; plasmids; receptor binding; tooth surface; transposon /insertion element

The focus of our research program is to understand the role of coaggregation in bacterial accretion of early colonizing bacteria on a clean tooth surface. The primary colonizers include actinomyces and streptococci. The 34.8-kDa lipoprotein surface-adhesin, ScaA, from Streptococcus gordonii PK488 is encoded as part of a 2.55 kb transcription unit consisting of three genes. This unit is a putative ATP-binding cassette operon similar to the operons encoding the binding-protein dependent transport systems of Gram-negative bacteria and the binding lipoprotein dependent transport systems of Gram-positive bacteria. ScaA probably is anchored in the cell membrane through its lipid moiety, while its receptor-recognizing binding site is exposed to the environment. Two coaggregation-relevant genes in Streptococcus gordonii DL1 have been identified by transposon mutagenesis and by integrative mutagenesis. By sequencing the DNA flanking the transposon, a close relationship was found to genes involved with synthesis of lipoteichoic acids, another class of surface molecules. The sequence flanking the erythromycin insertion plasmid had little homology with other sequences in the gene bank, but these mutants have lost a 100-kDa protein from their surface. This gene has been cloned and transformants regained the COG+ phenotype and the 100-kDa protein. It is proposed that the protein is an adhesin mediating intrageneric coaggregation. Actinomyces serovar WVA963 strain PK1259 exhibits only lactose-inhibitable coaggregation with streptococci. One of the spontaneous COG- mutants isolated excretes a 95-kDa protein that has been purified by lactose-agarose affinity beads and by binding to the partner streptococcal cells. Antiserum to the lactose-agarose bead preparation blocks coaggregation of the parent actinomyces with streptococci, suggesting that the 95-kDa protein is the adhesin mediating this coaggregation. The long range goal of these studies, collectively, is to elucidate the molecular mechanisms responsible for bacterial colonization in the human oral ecosystem.

我们研究计划的重点是了解 早期定殖细菌在一个 清洁牙齿表面。 主要定殖菌包括放线菌和 链球菌。 34.8-kDa脂蛋白表面粘附素，ScaA， 戈登链球菌PK488编码为2.55 kb转录的一部分 由三个基因组成。 这个单位是一个假定的ATP结合 类似于编码结合蛋白的操纵子的盒式操纵子 革兰氏阴性菌的依赖性转运系统及其结合 革兰氏阳性菌的脂蛋白依赖性转运系统。 SCAA 可能通过其脂质部分锚定在细胞膜上，而 其受体识别结合位点暴露于环境中。 戈登链球菌DL1中的两个共聚集相关基因已被克隆， 通过转座子诱变和整合诱变鉴定。 通过 对转座子侧翼的DNA进行测序，发现了一种密切的关系， 与合成脂磷壁酸有关的基因，另一类 表面分子 红霉素插入物侧翼的序列 质粒与基因库中其它序列同源性不高， 这些突变体从其表面失去了100-kDa的蛋白质。 该基因 已被克隆，转化体恢复了COG+表型， 100-kDa蛋白质。 推测该蛋白是一种粘附素， 属内共聚合 血清型放线菌WVA 963菌株PK 1259仅表现出乳糖降解性 与链球菌共聚集。 其中一个自发的COG突变体 分离的排泄物95-kDa的蛋白质，其已通过纯化 乳糖-琼脂糖亲和珠并通过与伴侣链球菌结合 细胞 乳糖-琼脂糖珠制备块的抗血清 亲放线菌与链球菌的共聚集，表明， 95-kDa蛋白是介导这种共聚集的粘附素。 长 这些研究的范围目标，总的来说，是阐明分子 人类口腔中细菌定植的机制 生态系统