ROLE OF SURFACE MOLECULES IN THE METABOLISM AND ECOLOGY OF ORAL BACTERIA

表面分子在口腔细菌代谢和生态中的作用

• 批准号: 3839216
• 负责人: J LONDON
• 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/3839216
• 关键词: Streptococcus infection; Streptococcus sanguis; adhesin; chromatography; dental plaque; ecology; gene expression; membrane activity; microorganism metabolism; molecular cloning; nucleic acid probes; oral bacteria; oxidoreductase; protein sequence

The 2.23 kb gene encoding the fimbrial-associated adhesin of P.loescheii PK1295 has been cloned and sequenced. The gene contains a ribosomal slip which results in a reading frame shift and a failure to translate the 28 bases found prior to the shift. Attempts to express the gene in a number of E.coli host strains have met with limited success. Clones containing vector-gene constructs appear to be near lethal; in the two instances where expression was observed both plasmid vector and gene were quickly lost. Presently, new strategies are being tested to stabilize constructs. The receptor for the Actinomyces israelii- specific fimbrial adhesin of P. loescheii has been extracted from the cells of A. israelii PK14 and purified by column chromatography. Preliminary results indicate that it contains neither protein nor carbohydrate reducing sugar, but the material does contain phosphorus. The purified material is capable of aggregating P. loescheii and certain Streptococcus sanguis cells. The gene encoding the xylitol and ribitol pathway enzymes are currently being cloned. A 6.2 kb chromosomal DNA fragment containing the entire ribitol-5-P dehydrogenase (RDH) gene has been ligated into pBluescript II SK and transformed into an E. coli host. Expression of the gene product was detected with anti-RDH IgG on immunoblots and active dehydrogenase was detected in cell extracts containing the cloned DNA. DNA fragments containing the xylitol-specific Factor III and xylitol-5-P dehydrogenase are currently being ligated into pBluescript II also.

罗氏假单胞菌菌毛相关粘附素的2.23kb编码基因 PK1295基因已被克隆并测序。该基因含有一个核糖体。 导致阅读框移位和翻译失败的滑移 在转移之前发现的28个基地。尝试在体内表达该基因 一些大肠杆菌宿主菌株已经取得了有限的成功。克隆人 含有载体基因结构似乎是近乎致命的；在这两个 同时观察到质粒载体和基因表达的实例 很快就迷路了。目前，新的战略正在进行测试，以 稳定构造物。以色列放线菌的受体- 罗氏拟青霉菌毛粘附素的提取 并用柱层析法对其进行纯化。 初步结果表明，它既不含蛋白质，也不含 碳水化合物还原糖，但这种材料确实含有磷。 提纯后的材料能够聚集洛氏假丝酵母和某些 血链球菌细胞。 编码木糖醇和核糖醇途径酶的基因目前 被克隆。一个6.2 kb的染色体DNA片段，包含整个 核糖醇-5-P脱氢酶基因已连接到pBluescrip中 Ii SK，转化到大肠杆菌宿主中。基因的表达 免疫印迹检测产物用抗RDHIg G进行活性检测 在含有克隆DNA的细胞提取液中检测到脱氢酶。 含有木糖醇特异因子III和木糖醇-5-P的DNA片段 脱氢酶目前也连接到pBluescrip II中。