• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Infection and immunity >Roles of Fructosyltransferase and Levanase-Sucrase of Actinomyces naeslundii in Fructan and Sucrose Metabolism
【24h】

Roles of Fructosyltransferase and Levanase-Sucrase of Actinomyces naeslundii in Fructan and Sucrose Metabolism

机译：内脏放线菌的果糖基转移酶和蔗糖蔗糖酶在果聚糖和蔗糖代谢中的作用

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The ability of Actinomyces naeslundii to convert sucrose to extracellular homopolymers of fructose and to catabolize these types of polymers is suspected to be a virulence trait that contributes to the initiation and progression of dental caries and periodontal diseases. Previously, we reported on the isolation and characterization of the gene, ftf, encoding the fructosyltransferase (FTF) of A. naeslundii WVU45. Allelic exchange mutagenesis was used to inactivate ftf, revealing that FTF-deficient stains were completely devoid of the capacity to produce levan-type (β2,6-linked) polysaccharides. A polyclonal antibody was raised to a histidine-tagged, purified A. naeslundii FTF, and the antibody was used to localize the enzyme in the supernatant fluid. A sensitive technique was developed to detect levan formation by proteins that had been separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the method was used to confirm that the levan-synthesizing activity of A. naeslundii existed predominantly in a cell-free form, that a small amount of the activity was cell associated, and that theftf mutant was unable to produce levans. By using the nucleotide sequence of the levanase gene of a genospecies 2 A. naeslundii, formerly Actinomyces viscosus, a portion of a homologue of this gene (levJ) was amplified by PCR and inserted into a suicide vector, and the resulting construct was used to inactivate the levJ gene in the genospecies 1 strain WVU45. A variety of physiologic and biochemical studies were performed on the wild-type and LevJ-deficient strains to demonstrate that (i) this enzyme was the dominant levanase and sucrase of A. naeslundii; (ii) that LevJ was inducible by growth in sucrose; (iii) that the LevJ activity was found predominantly (>90%) in a cell-associated form; and (iv) that there was a second, fructose-inducible fructan hydrolase activity produced by these strains. The data provide the first detailed molecular analysis of fructan production and catabolism in this abundant and important oral bacterium.
机译：Naemlundii放线菌将蔗糖转化为果糖的细胞外均聚物并分解这些类型的聚合物的能力被认为是一种致病性状，有助于龋齿和牙周疾病的发生和发展。以前，我们报道了编码 A的果糖基转移酶（FTF）的基因 ftf 的分离和鉴定。 naeslundii WVU45。等位基因交换诱变用于灭活 ftf ，这表明缺乏FTF的染色剂完全没有产生Levan型（β2，6-连接的）多糖的能力。将多克隆抗体升高至组氨酸标记的纯化的 A。 Naeslundii FTF，并使用抗体在上清液中定位酶。开发了一种灵敏的技术来检测十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分离的蛋白质形成的莱文，并使用该方法确认 A的莱文合成活性。 naeslundii 主要以无细胞形式存在，少量的活性与细胞有关，而 ftf 突变体不能产生levan。通过使用基因组2 A的levanase基因的核苷酸序列。 naeslundii （以前是粘性放线菌），通过PCR扩增了该基因的一部分同源物（ levJ ），并插入了自杀载体，并构建了构建体被用于灭活基因1号菌株WVU45中的 levJ 基因。对野生型和LevJ缺陷型菌株进行了各种生理和生化研究，以证明（i）该酶是 A的主要左旋糖酶和蔗糖酶。 naeslundii ; （ii）LevJ是由蔗糖的生长诱导的; （iii）主要以细胞相关形式发现LevJ活性（> 90％）; （iv）这些菌株产生了第二种果糖诱导的果聚糖水解酶活性。数据提供了这种丰富而重要的口腔细菌中果聚糖产生和分解代谢的第一个详细的分子分析。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号